Skip to main content
Log in

An inverse controller design method for interval type-2 fuzzy models

  • Methodologies and Application
  • Published:
Soft Computing Aims and scope Submit manuscript

Abstract

Recently, it has been demonstrated that interval type-2 (IT2) fuzzy sets and systems are powerful tools in representing and controlling nonlinear systems. Thus, an inverse IT2 fuzzy model (FM) based controller might be an efficient way to control nonlinear processes. In this context, IT2-FM inversion methods have been proposed and successfully implemented in control system design. In this study, an analytical methodology has been developed to form the exact inverse of a certain class of IT2-FM. The proposed inversion methodology consists of two main steps, decomposing the IT2-FM into submodels and then finding the inverse of each possible activated interval type-2 fuzzy submodel. In order to form the inverse IT2-FM controller, the analytical formulation of the interval type-2 fuzzy submodel output is tried to be reached for an inverse solution since the IT2-FM output cannot be presented in a closed form due to the Karnik–Mendel type reduction method. Thus, to form the exact inverse type-2 fuzzy model, an iterative algorithm based on an analytical methodology is proposed to overcome this problem. The proposed inverse controller is embedded into a nonlinear internal model control scheme to provide an effective closed loop control performance in the presence of modelling mismatches and disturbances. Comparative simulation studies have been given where the beneficial sides of the proposed inverse controller are shown clearly in comparison to its type-1 and conventional counterpart.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19

Similar content being viewed by others

References

  • Abonyi J (2003) Fuzzy model identification for control. Birkhauser, Boston

    Book  MATH  Google Scholar 

  • Astrom KJ, Hagglund T (2005) Advanced PID control. ISA—The Instrumentation, Systems, and Automation Society, Research Triangle Park

  • Babuska R (1998) Fuzzy modeling for control. Kluwer, Boston

    Book  Google Scholar 

  • Biglarbegian M, Melek W, Mendel J (2011) On the robustness of type-1 and interval type-2 fuzzy logic systems in modeling. Inf Sci 181:1325–1347

    Article  MathSciNet  MATH  Google Scholar 

  • Boukezzoula R, Galichet S, Folloy L (2003) Nonlinear internal model control: application of inverse model based fuzzy control. IEEE Trans Fuzzy Syst 11(6):814–829

    Article  Google Scholar 

  • Castillo O, Patricia P (2014) A review on interval type-2 fuzzy logic applications in intelligent control. Inf Sci 279:615–631

    Article  MathSciNet  MATH  Google Scholar 

  • Economou G, Morari M, Palsson B (1986) Internal model control: extension to nonlinear systems. Ind Eng Chem Process Des Dev 25:403–411

    Article  Google Scholar 

  • El-Nagar AM, El-Bardini M (2010) Simplified interval type-2 fuzzy logic system based on new type-reduction approach. J Intell Fuzzy Syst 27:1999–2010

    MATH  Google Scholar 

  • Faccin F, Trierweiler JO (2004) A novel tool for multi-model PID controller design. In: 7th international symposium on dynamics and control of process systems, Cambridge, 5- 7 July 2004

  • Fuente MJ, Robles C, Casado O, Syafiie S, Tadeo F (2006) Fuzzy control of a neutralization process. Eng Appl Artif Intell 19:905–914

    Article  Google Scholar 

  • Garcia CE, Morari M (1982) Internal model control-1. A unifying review and some new results. Ind Eng Chem Process Des Dev 21(2):308–323

  • Hagras H (2004) A hierarchical type-2 fuzzy logic control architecture for autonomous mobile robots. IEEE Trans Fuzzy Syst 12(4):524–539

    Article  Google Scholar 

  • Kumbasar T (2014) A simple design method for interval type-2 fuzzy PID controllers. Soft Comput 18(7):1293–1304

    Article  Google Scholar 

  • Kumbasar T, Hagras H (2014) Big bang-big crunch optimization based interval type-2 fuzzy PID cascade controller design strategy. Inf Sci 282:277–295

    Article  Google Scholar 

  • Kumbasar T, Eksin I, Guzelkaya M, Yesil E (2011) Interval type-2 fuzzy inverse controller design in nonlinear IMC structure. Eng Appl Artif Intell 24(6):996–1005

    Article  MATH  Google Scholar 

  • Kumbasar T, Eksin I, Guzelkaya M, Yesil E (2011) Adaptive fuzzy model based inverse controller design using BB-BC optimization. Expert Syst Appl 38:12356–12364

    Article  Google Scholar 

  • Kumbasar T, Eksin I, Guzelkaya M, Yesil E (2012) Type-2 fuzzy model based controller design for neutralization processes. ISA Trans 51(2):277–287

    Article  MATH  Google Scholar 

  • Kumbasar T, Eksin I, Guzelkaya M, Yesil E (2015) Exact Inversion of decomposable interval type-2 fuzzy logic systems. Int J Approx Reas 54(2):253–272

  • Lam HK, Li H, Deters C, Wuerdemann H, Secco E, Althoefer K (2014) Control design for interval type-2 fuzzy systems under imperfect premise matching. IEEE Trans Ind Electron 61(2):956–968

    Article  Google Scholar 

  • Liang Q, Mendel JM (2000) Interval type-2 fuzzy logic systems: theory and design. IEEE Trans Fuzzy Syst 8(5):535–550

    Article  Google Scholar 

  • Lu Q, Shi P, Lam HK, Zhao Y (2015) Interval type-2 fuzzy model predictive control of nonlinear networked control systems. IEEE Trans Fuzzy Syst (article in press)

  • Mendel J (2000) Uncertain rule-based fuzzy logic: introduction and new directions. Prentice Hall, USA

    MATH  Google Scholar 

  • Mendel JM, Liu F (2007) Super-exponential convergence of the Karnik–Mendel algorithms for computing the centroid of an interval type-2 fuzzy set. IEEE Trans Fuzzy Syst 15(2):309–320

    Article  Google Scholar 

  • Mendel J, John R, Liu F (2006) Interval type-2 fuzzy logic systems made simple. IEEE Trans Fuzzy Syst 14(6):808–821

    Article  Google Scholar 

  • Mendel J, Hagras H, Tan WW, Melek WW, Ying H (2014) Introduction to type-2 fuzzy logic control: theory and applications. Wiley, New York

  • Morari M, Zafiriou E (1989) Robust process control. Prentice-Hall, Englewood Cliffs

    MATH  Google Scholar 

  • Precup R-E, Hellendoorn H (2011) A survey on industrial applications of fuzzy control. Comput Ind 62:213–226

    Article  Google Scholar 

  • Wang D, Kazuo A (2003) Research on fuzzy I-PD preview control for nonlinear system. JSME Int J Ser C Spec Issue Adv Motion Vib Control Technol 46(3):1042–1050

    Google Scholar 

  • Wu D (2012) On the fundamental differences between interval type-2 and type-1 fuzzy logic controllers. IEEE Trans Fuzzy Syst 10(5):832–848

    Article  Google Scholar 

  • Wu D (2013) Approaches for reducing the computational cost of interval type-2 fuzzy logic controllers: overview and comparison. IEEE Trans Fuzzy Syst 21:80–99

    Article  Google Scholar 

  • Wu H, Mendel JM (2002) Uncertainty bounds and their use in the design of interval type-2 fuzzy logic systems. IEEE Trans Fuzzy Syst 10:622–639

    Article  Google Scholar 

  • Wu D, Mendel JM (2008) Enhanced Karnik–Mendel algorithms. IEEE Trans Fuzzy Syst 17(4):923–934

    Google Scholar 

  • Wu D, Tan WW (2006) Genetic learning and performance evaluation of internal type-2 fuzzy logic controllers. Eng Appl Artif Intell 19:829–841

    Article  Google Scholar 

  • Zeng X-J, Singh MG (1996) Decomposition property of fuzzy systems and its applications. IEEE Trans Fuzzy Syst 4(2):149–165

    Article  Google Scholar 

Download references

Acknowledgments

The authors would like to acknowledge the financial support from the Institute of Science and Technology of Istanbul Technical University (SPR-BAP 34492).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Tufan Kumbasar.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Communicated by V. Loia.

Appendices

Appendix 1

Here, it will be shown that (48) can be formulated as (50) for each possible value of \({ L}_{{ c}}{ L}_{ c} \in \left\{ {1,2,3} \right\} \).

$$\begin{aligned} 0= & {} -( {{ y}_{\mathrm{des}} -\gamma })\left( {\sum \limits _{{ j}=1}^{{ L}_{ c} } {\overline{ f}^{ j}} +\sum \limits _{{ j}={ L}_{ c} +1}^{ N} {\underline{{ f}^{ j}}} } \right) \nonumber \\&+\left( {\sum \limits _{{ j}=1}^{{ L}_{ c} } {\overline{{ f}^{ j}} \underline{{ c}}_{ j} +\sum \limits _{{ j}={ L}_{ c} +1}^{ N} {\underline{{ f}^{ j}}\underline{{ c}}_{ j}} } }\right) \end{aligned}$$
(48)

where the total firing set is:

$$\begin{aligned}&{\underline{f}^{1}}=[ {\underline{\mu }{\tilde{{ A}}}_{1}^{1} \underline{\mu }\tilde{{ B}}_1^{1} } ] \quad \overline{f }^1=[ {{\overline{ \mu }} {\tilde{{ A}}}_{1}^{1} {\overline{ \mu }} \tilde{{ B}}_{1}^{1} } ]\nonumber \\&{{\underline{f}^{2}}=[ {\underline{\mu }{\tilde{ A}}_{1}^{1} \underline{\mu }\tilde{{ B}}_{1}^{2} } ]} \quad \overline{f }^2=[ {{\overline{ \mu }} {\tilde{ A}}_{1}^{1} {\overline{ \mu }} \tilde{{ B}}_{1}^{2} } ]\nonumber \\&{{\underline{f}^{3}}=[ {\underline{{ \mu }}{{\tilde{ A}}_{1}^{2}} \underline{\mu }\tilde{{ B}}_{1}^{1} } ]} \quad \overline{f }^3=[ {{\overline{ \mu }} {\tilde{ A}}_{1}^{2} {\overline{ \mu }} \tilde{{ B}}_{1}^{1} } ] \nonumber \\&{{\underline{f}^{4}}=[ {\underline{{ \mu }}{\tilde{ A}}_{1}^{2} \underline{{ \mu }}\tilde{{ B}}_{1}^{2} } ]} \quad \overline{f }^4=[ {{\overline{ \mu }} {\tilde{ A}}_{1}^{2} {\overline{ \mu }} \tilde{{ B}}_{1}^{2} } ] \end{aligned}$$
(49)
$$\begin{aligned} \psi _{1}^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_{1}^{1} +\psi _{2}^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_{1}^{2} +\psi _{3}^{{ L}} (.)\underline{{ \mu }} \tilde{{ B}}_{1}^{2} +\psi _{4}^{{ L}} (.)\underline{{ \mu }}\tilde{{ B}}_{1}^{1} =0\nonumber \\ \end{aligned}$$
(50)

Here \(\psi _{{ i}}^{{ L}} (.),{{ i}}=1,...,4\) is a function of \(( {{{ y}}_{\mathrm{des}} ,\gamma ,\underline{{ c}}_{{ j}} })\) and a possible combination of the following parameters \({\overline{\mu }} {\tilde{{ A}}}_{1}^{1} ,{\overline{\mu }} \tilde{{ A}}_{1}^{2} ,\underline{{ \mu }}{\tilde{{ A}}}_{1}^{2}\, \text{ and }\, \underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} \).

(i) For \({ L}_{{ c}} =1\), (48) can be formulated as:

$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} -\gamma })\left( {\sum \limits _{{ j}=1}^{{{ L}}_{{ c}} =1} {\overline{{ f}}^{{ j}}} +\sum \limits _{{{ j}}={{ L}}_{{ c}} +1}^{{{ N}}=4} {\underline{{{ f}}^{{ j}}}}}\right) \nonumber \\&+\left( {\sum \limits _{{{ j}}=1}^{{{ L}}_{{ c}} =1} {\overline{{ f}}^{{ j}}} \underline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ L}}_{{ c}} +1}^{{{ N}}=4} \underline{{{ f}}^{{ j}}}{\underline{{ c}}_{{ j}} } }\right) \end{aligned}$$
(51)
$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} -\gamma })( {\overline{{ f}^1} +{\underline{{ f}}^{2}}+{\underline{{ f}}^{3}}+\underline{{{ f}}^{4}}})\nonumber \\&+( {\underline{{ c}}_{1} \overline{{{ f}}^1} +\underline{{ c}}_{2} {\underline{{ f}}^{2}} +\underline{{ c}}_{3} {\underline{{ f}}^{3}}+ \underline{{ c}}_{4} \underline{{{ f}}^{4}}}) \end{aligned}$$
(52)
$$\begin{aligned} 0= & {} \overline{{{ f}}^1} ( {1}+\underline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+{\underline{{ f}}^2}({1} +\underline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+ \cdots \nonumber \\&\cdots +{\underline{{ f}}^3}( {1} +\underline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+\underline{{{ f}}^4}( {1} +\underline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} +\gamma }))\nonumber \\ \end{aligned}$$
(53)

Replacing total interval firing set (49) into (54), we can obtain:

$$\begin{aligned} 0= & {} ( {{\overline{ u}} {\tilde{ A}}_{1}^{1} {\overline{ u}} \tilde{{ B}}_{1}^{1} })( {1}+\underline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} +\gamma }))\nonumber \\&+( {\underline{\mu }{\tilde{{ A}}}_{1}^{1} \underline{\mu }\tilde{{ B}}_{1}^{2} })( {1} +\underline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+\cdots \nonumber \\&\cdots +( {\underline{\mu }{\tilde{{ A}}}_{1}^{2} \underline{\mu }\tilde{{ B}}_{1}^{1} })( {1} +\underline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} +\gamma }))\nonumber \\&+( {\underline{\mu }{\tilde{ A}}_{1}^{2} \underline{\mu }\tilde{{ B}}_{1}^{2} })({1} +\underline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} +\gamma })) \end{aligned}$$
(54)

Reformulating (55)

$$\begin{aligned} 0= & {} ( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_1 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_1 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} })\overline{\mu }\tilde{{ B}}_1^1 +( 0){\overline{\mu }} \tilde{{ B}}_1^2 +\cdots \nonumber \\&\cdots +( \underline{\mu }{\tilde{{ A}}}_{1}^{1} +\underline{\mu }{\tilde{{ A}}}_{1}^{2} +\underline{{ c}}_{2} \gamma \underline{\mu }{\tilde{{ A}}}_{1}^{1} +\underline{{ c}}_{4} \gamma \underline{\mu }{\tilde{{ A}}}_{1}^{2}\nonumber \\&-\underline{{ c}}_{2} \underline{\mu }\tilde{{ A}}_{1}^{1} {{ y}}_{\mathrm{des}} -\underline{{ c}}_{4} \underline{\mu }{\tilde{{ A}}}_{1}^{2} {{ y}}_{\mathrm{des}} )\underline{\mu }\tilde{{ B}}_{1}^{2} \nonumber \\&\cdots +( {\underline{\mu }{\tilde{{ A}}}_{1}^{2} +\underline{{ c}}_{3} \gamma \underline{\mu }{\tilde{{ A}}}_{1}^{2} -\underline{{ c}}_{3} \underline{{ \mu }}{\tilde{{ A}}}_{1}^{2} {{ y}}_{\mathrm{des}} })\underline{{ \mu }}\tilde{{ B}}_{1}^{1} \end{aligned}$$
(55)

Then the following expression is obtained:

$$\begin{aligned} \psi _1^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_1^1 +\psi _2^{ {L}} (.){\overline{\mu }} \tilde{{ B}}_1^2 +\psi _3^{{ L}} (.)\underline{\mu }\tilde{{ B}}_1^2 +\psi _4^{{ L}} (.)\underline{\mu }\tilde{{ B}}_1^1 =0\nonumber \\ \end{aligned}$$
(56)

where

$$\begin{aligned} \psi _1^{{ L}} (.)&=( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_1 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_1 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} }) \nonumber \\ \psi _2^{{ L}} (.)&=0 \nonumber \\ \psi _3^{{ L}} (.)&=( \underline{\mu }{\tilde{{ A}}}_1^1 +\underline{\mu }{\tilde{{ A}}}_1^2 +\underline{{ c}}_2 \gamma \underline{\mu }{\tilde{{ A}}}_1^1 +\underline{{ c}}_4 \gamma \underline{\mu }{\tilde{{ A}}}_1^2\nonumber \\&\quad -\underline{{ c}}_2 \underline{\mu }{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} -\underline{{ c}}_4 \underline{\mu }{\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}}) \nonumber \\ \psi _4^{{ L}} (.)&=( {\underline{{ \mu }}{\tilde{{ A}}}_1^2 +\underline{{ c}}_3 \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^2 -\underline{{ c}}_3 \underline{{ \mu }}{\tilde{{ A}}}_1^2 {{ y}}_{{ \mathrm{des}}} }) \end{aligned}$$
(57)

(ii) For \({ L}_{{ c}}=2\), (48) can be formulated as:

$$\begin{aligned} 0= & {} -\left( {{{ y}}_{\mathrm{des}} -\gamma }\right) \left( {\sum \limits _{{{ j}}=1}^{{{ L}}_{{ c}} =2} {\overline{{ f}}^{ j}} +\sum \limits _{{{ j}}={{ L}}_{{ c}} +1}^{{{ N}}=4} {\underline{{{ f}}^{{ j}}}} } \right) \nonumber \\&+\left( {\sum \limits _{{{ j}}=1}^{{{ L}}_{{ c}} =2} {\overline{{ f}}^{{ j}}} \underline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ L}}_{{ c}} +1}^{{{ N}}=4} {\underline{{{ f}}^{{ j}}}\underline{{ c}}_{{ j}} } } \right) \end{aligned}$$
(58)
$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} -\gamma })({\overline{{ f}}^{1}}+{\overline{{ f}}^{2}}+{\overline{{ f}}^{3}}+{\overline{{ f}}^{4}})\nonumber \\&+(\underline{{ c}}_{1}{\overline{{ f}}^{1}}+\underline{{ c}}_{2}{\overline{{ f}}^{2}}+\underline{{ c}}_{3}\underline{{ f}}_{3}+ \underline{{ c}}_{4}\underline{{ f}}_{4}) \end{aligned}$$
(59)
$$\begin{aligned} 0&=\overline{{{ f}}^1} ( {1}+\underline{{ c}}_1 ( {-{{ y}}_\mathrm{\mathrm{des}} +\gamma }))+\overline{{{ f}}^2} ( {1} +\underline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+\cdots \nonumber \\&\quad \cdots +{\underline{{ f}}^3}( {1} +\underline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+\underline{{{ f}}^4}( {1} +\underline{{ c}}_4 ( {-{{ S}}_{\mathrm{des}} +\gamma }))\nonumber \\ \end{aligned}$$
(60)

Replacing total interval firing set (49) into (61)

$$\begin{aligned} 0= & {} \left( \overline{\mu }\tilde{A}^1_1+\underline{c}_1\gamma \overline{\mu }\tilde{A}^1_1-\underline{c}_1 \overline{\mu }\tilde{A}^1_1y_\mathrm{des}\right) \overline{\mu }\tilde{B}^1_1\nonumber \\&+ \left( \overline{\mu }\tilde{A}^1_1+\underline{c}_2\gamma \overline{\mu }\tilde{A}^1_1-\underline{c}_2 \overline{\mu }\tilde{A}^1_1y_\mathrm{des}\right) \overline{\mu }\tilde{B}^2_1\ldots \nonumber \\&\ldots +\left( \underline{\mu }\tilde{A}^2_1+\underline{c}_4\gamma \underline{\mu }\tilde{A}^2_1 -\underline{c}_4 \underline{\mu }\tilde{A}^2_1y_\mathrm{des}\right) \overline{\mu }\tilde{B}^2_1\nonumber \\&+ \left( \underline{\mu }\tilde{A}^2_1+\underline{c}_3\gamma \underline{\mu }\tilde{A}^2_1-\underline{c}_3 \underline{\mu }\tilde{A}^2_1y_\mathrm{des}\right) \overline{\mu }\tilde{B}^1_1 \end{aligned}$$
(61)

Reformulating (62)

$$\begin{aligned} 0= & {} ( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_1 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_1 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} })\overline{\mu }\tilde{{ B}}_1^1\nonumber \\&+( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_2 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_2 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} }){\overline{\mu }} \tilde{{ B}}_1^2 +\cdots \nonumber \\&\cdots +( {\underline{\mu }{\tilde{{ A}}}_1^2 +\underline{{ c}}_4 \gamma \underline{\mu }{\tilde{{ A}}}_1^2 -\underline{{ c}}_4 \underline{\mu }{\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} })\underline{\mu }\tilde{ B}_1^2\nonumber \\&+( {\underline{\mu }\tilde{{ A}}_1^2 +\underline{{ c}}_3 \gamma \underline{\mu }\tilde{{ A}}_1^2 -\underline{{ c}}_3 \underline{\mu }\tilde{{ A}}_1^2 {{ y}}_{\mathrm{des}} })\underline{\mu }\tilde{{ B}}_1^1 \end{aligned}$$
(62)

Then the following expression is obtained:

$$\begin{aligned} \psi _1^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_1^1 +\psi _2^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_1^2 +\psi _3^{{ L}} (.)\underline{{ \mu }}\tilde{{ B}}_1^2 +\psi _4^{{ L}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 =0\nonumber \\ \end{aligned}$$
(63)

where

$$\begin{aligned}&\psi _1^{{ L}} (.)=( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_1 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_1 {\overline{\mu }} {\tilde{{ A}}}_2^1 {{ y}}_{\mathrm{des}} }) \nonumber \\&\psi _2^{{ L}} (.)=( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_2 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_2 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} }) \nonumber \\&\psi _3^{{ L}} (.)=( {\underline{\mu }{\tilde{{ A}}}_1^2 +\underline{{ c}}_4 \gamma \underline{\mu }{\tilde{{ A}}}_1^2 -\underline{{ c}}_4 \underline{\mu }{\tilde{{ A}}}} _1^2 {{ y}}_{\mathrm{des}} ) \nonumber \\&\psi _4^{{ L}} (.)=( {\underline{{ \mu }}{\tilde{{ A}}}_1^2 +\underline{{ c}}_3 \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^2 -\underline{{ c}}_3 \underline{{ \mu }}{\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} }) \end{aligned}$$
(64)

(iii) For \({ L}_{{ c}}=3\), (48) can be formulated as:

$$\begin{aligned}&0=-\left( {{{ y}}_{\mathrm{des}} -\gamma }\right) \left( {\sum \limits _{{{ j}}=1}^{{{ L}}_{{ c}} =3} {\overline{{ f}}^{{ j}}} +\sum \limits _{{{ j}}={{ L}}^{*} +1}^{{{ N}}=4} {\underline{{{ f}}^{{ j}}}} } \right) \nonumber \\&\quad \qquad +\left( {\sum \limits _{{{ j}}=1}^{{{ L}}_{{ c}} =3} {\overline{{ f}}^{{ j}}} \underline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ L}}^{*} +1}^{{{ N}}=4} {\underline{{{ f}}^{{ j}}}\underline{{ c}}_{{ j}} } }\right) \end{aligned}$$
(65)
$$\begin{aligned}&0=-\left( {{{ y}}_{\mathrm{des}} -\gamma }\right) ( {\overline{{{ f}}^{1}} +\overline{{{ f}}^2} +\overline{{{ f}}^{3}} +\underline{{{ f}}^{4}}})\nonumber \\&\quad \,\,\quad +( {\underline{{ c}}_1 \overline{{{ f}}^{1}} +\underline{{ c}}_{2} \overline{{{ f}}^{2}} +\underline{{ c}}_{3} \overline{{{ f}}^{3}} +\underline{{ c}}_4 \underline{{{ f}}^{4}}}) \end{aligned}$$
(66)
$$\begin{aligned}&0=\overline{{{ f}}^1} ( {1}+\underline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+\overline{{{ f}}^2} ( {1} +\underline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+ \cdots \nonumber \\&\quad \cdots +\overline{{{ f}}^3} ( {1} +\underline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} +\gamma }))+\underline{{{ f}}^4}( {1} +\underline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} +\gamma }))\nonumber \\ \end{aligned}$$
(67)

Replacing total interval firing set (49) into (68)

$$\begin{aligned}&0=( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{1} {\overline{\mu }} \tilde{{ B}}_{1}^{1} })\left( {1}+\underline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} +\gamma })\right) +( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{1} {\overline{\mu }} \tilde{{ B}}_{1}^{2} })\nonumber \\&\quad \quad \times \left( {1} +\underline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} +\gamma })\right) + \cdots \nonumber \\&\quad \quad \cdots +( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{1} })\left( {1} +\underline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} +\gamma })\right) +( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{2} })\nonumber \\&\quad \quad \times \left( {1} +\underline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} +\gamma })\right) \end{aligned}$$
(68)

Reformulating (69)

$$\begin{aligned} 0&=({\overline{\mu }} {\tilde{{ A}}}_1^1 +{\overline{\mu }} \tilde{{ A}}_1^2 +\underline{{ c}}_1 \gamma {\overline{\mu }} \tilde{{ A}}_1^1 -\underline{{ c}}_1 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}}\nonumber \\&\quad \quad +\underline{{ c}}_3 {\overline{\mu }} \tilde{{ A}}_1^2 -\underline{{ c}}_3 {\overline{\mu }} \tilde{{ A}}_1^2 {{ y}}_{\mathrm{des}}){\overline{\mu }} \tilde{{ B}}_1^1 \nonumber \\&\quad \quad +( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_2 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_2 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} })\overline{\mu }\tilde{{ B}}_1^2\nonumber \\&\quad \quad +( {\underline{{ \mu }}{\tilde{{ A}}}_1^2 +\underline{{ c}}_4 \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^2 -\underline{{ c}}_4 \underline{{ \mu }}{\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} })\underline{\mu }\tilde{{ B}}_1^2 +\left( 0\right) \underline{{ \mu }}\tilde{{ B}}_1^1 \end{aligned}$$
(69)

Then the following expression is obtained:

$$\begin{aligned} \psi _1^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_1^1 +\psi _2^{{ L}} (.){\overline{\mu }} \tilde{{ B}}_1^2 +\psi _3^{{ L}} (.)\underline{{ \mu }}\tilde{{ B}}_1^2 +\psi _4^{{ L}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 =0\nonumber \\ \end{aligned}$$
(70)

where

$$\begin{aligned}&\psi _1^{{ L}} (.)={\overline{\mu }} {\tilde{{ A}}}_1^1 +\overline{\mu }{\tilde{{ A}}}_1^2 +\underline{{ c}}_1 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_1 {\overline{\mu }} \tilde{{ A}}_1^1 {{ y}}_{\mathrm{des}}\nonumber \\&\qquad \quad \ \quad +\,\underline{{ c}}_3 \overline{\mu }{\tilde{{ A}}}_1^2 -\underline{{ c}}_3 {\overline{\mu }} \tilde{{ A}}_1^2 {{ y}}_{\mathrm{des}} \nonumber \\&\psi _2^{{ L}} (.)=( {{\overline{\mu }} {\tilde{{ A}}}_1^1 +\underline{{ c}}_2 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 -\underline{{ c}}_2 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} }) \nonumber \\&\psi _3^{{ L}} (.)=( {\underline{{ \mu }}{\tilde{{ A}}}_1^2 +\underline{{ c}}_4 \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^2 -\underline{{ c}}_4 \underline{{ \mu }}{\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} }) \nonumber \\&\psi _4^{{ L}} (.)=( 0) \end{aligned}$$
(71)

As it has been shown above, (48) can be represented in form given in (50) for each possible value of \({ L}_{{ c}} ( { L}_{ c} \in \left\{ {1,2,3} \right\} )\).

Appendix 2

In this part, it will be shown that (72) can be formulated as (74) for each possible value of \({{ R}}_{{ c}} \in \left\{ {1,2,3} \right\} \).

$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}} } {\underline{{ f}}^{{ j}}+\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}} } }\right) \nonumber \\&+\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}}} {\underline{{{ f}}}^{{ j}}\overline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}\overline{{ c}}_{{ j}}}}}\right) \end{aligned}$$
(72)

where the total firing set is:

$$\begin{aligned}&{\underline{{{ f}}}^{{1}}=[ {\underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} \underline{{ \mu }}\tilde{{ B}}_1^{1} } ]} \quad {\overline{{{ f}}}^1=[ {{\overline{\mu }} {\tilde{{ A}}}_{1}^{1} {\overline{\mu }} \tilde{{ B}}_{1}^{1} } ]} \nonumber \\&{\underline{{{ f}}}^{{2}}=[ {\underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} \underline{{ \mu }}\tilde{{ B}}_{1}^{2} } ]} \quad {\overline{{ f}}^2=[ {{\overline{\mu }} {\tilde{{ A}}}_{1}^{1} {\overline{\mu }} \tilde{{ B}}_{1}^{2} } ]} \nonumber \\&{\underline{{{ f}}}^{{3}}=[ {\underline{\mu }{\tilde{{ A}}}_{1}^{2} \underline{{ \mu }}\tilde{{ B}}_{1}^{1} } ]} \quad {\overline{{ f}}^3=[ {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{1} } ]} \nonumber \\&{\underline{{{ f}}}^{{4}}=[ {\underline{{ \mu }}{\tilde{{ A}}}_{1}^{2} \underline{{ \mu }}\tilde{{ B}}_{1}^{2} } ]} \quad {\overline{{ f}}^4=[ {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{2} } ]} \end{aligned}$$
(73)
$$\begin{aligned} \psi _1^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 +\psi _2^{{ R}} (.){\overline{\mu }} \tilde{{ B}}_1^2 +\psi _3^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^2 +\psi _4^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 =0\nonumber \\ \end{aligned}$$
(74)

where \(\psi _{{ i}}^{{ R}} (.),{{ i}}=1,...,4\) is a function of \(( {{{ y}}_{\mathrm{des}} ,\gamma ,\overline{{ c}} _{{ j}} })\) and a possible combination of the following parameters \(( {{\overline{ u}} {\tilde{{ A}}}_1^1 ,{\overline{ u}} \tilde{{ A}}_1^2 ,\underline{{ u}}{\tilde{{ A}}}_1^2 ,\underline{\mu }{\tilde{{ A}}}_1^1 })\).

(i) For \({{ R}}_{{ c}} =1\), (72) can be formulated as:

$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}} =1} {\underline{{ f}}^{{ j}}+\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}} } }\right) \nonumber \\&+\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}} =1} {\underline{{ f}}^{{ j}}\overline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}\overline{{ c}}_{{ j}} } } }\right) \end{aligned}$$
(75)
$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })( {\underline{{{ f}}}^1}+\overline{{{ f}}^2} +\overline{{{ f}}^3} +\overline{{{ f}}^4} )\nonumber \\&+( {\overline{{ c}}_1 \underline{{{ f}}^1}+\overline{{ c}}_2 \overline{{{ f}}^2} + \overline{{ c}}_3 \overline{{{ f}}^3} +\overline{{ c}}_4 \overline{{{ f}}^4} }) \end{aligned}$$
(76)
$$\begin{aligned} 0= & {} \underline{{{ f}}^1}\left( {1}+\overline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) +\overline{{{ f}}^2} \left( {1} +\overline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) + \cdots \nonumber \\&\cdots + \overline{{{ f}}^3} \left( {1} +\overline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) +\overline{{{ f}}^4} \left( {1} +\overline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) \nonumber \\ \end{aligned}$$
(77)

Replacing total interval firing set (73) into (78)

$$\begin{aligned} 0= & {} ( {\underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} \underline{\mu }\tilde{{ B}}_1^{1} })( {1}+\overline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} -\gamma }))\nonumber \\&+( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{1} {\overline{\mu }} \tilde{{ B}}_{1}^{2} })( {1} +\overline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} -\gamma }))+ \cdots \nonumber \\&\cdots +( {{\overline{\mu }} {\tilde{ A}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{1} })( {1} +\overline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} -\gamma }))\nonumber \\&+( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{2} })( {1} +\overline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} -\gamma })) \end{aligned}$$
(78)

Reformulating (78)

$$\begin{aligned} 0= & {} ( {{\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} }){\overline{\mu }} \tilde{{ B}}_1^1 \nonumber \\&+\cdots +({\overline{\mu }} {\tilde{{ A}}}_1^1 +{\overline{\mu }} \tilde{{ A}}_1^2 +\overline{{ c}}_2 \gamma {\overline{\mu }} \tilde{{ A}}_1^1 +\overline{{ c}}_4 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_2 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}}\nonumber \\&-\overline{{ c}}_4 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}}){\overline{\mu }} \tilde{{ B}}_1^2 +\cdots \nonumber \\&\cdots +( 0)\underline{{ \mu }}\tilde{{ B}}_1^2 +( {\underline{\mu }{\tilde{{ A}}}_1^1 -\overline{{ c}}_1 \gamma \underline{\mu }{\tilde{{ A}}}_1^1 -\overline{{ c}}_1 \underline{{ \mu }}\tilde{{ A}}_1^1 {{ y}}_{\mathrm{des}} })\underline{\mu }\tilde{{ B}}_1^1\nonumber \\ \end{aligned}$$
(79)

Then the following expression is obtained:

$$\begin{aligned} \psi _1^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 +\psi _2^{{ R}} (.){\overline{\mu }} \tilde{{ B}}_1^2 +\psi _3^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^2 +\psi _4^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 =0\nonumber \\ \end{aligned}$$
(80)

where

$$\begin{aligned}&\psi _1^{{ R}} (.)=( {{\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} }) \nonumber \\&\psi _2^{{ R}} (.)=({\overline{\mu }} {\tilde{{ A}}}_1^1 +{\overline{\mu }} {\tilde{{ A}}}_1^2 +\overline{{ c}}_2 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^1 +\overline{{ c}}_4 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2\nonumber \\&\qquad \quad \qquad -\overline{{ c}}_2 {\overline{\mu }} {\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} -\overline{{ c}}_4 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}}) \nonumber \\&\psi _3^{{ R}} (.)=( 0) \nonumber \\&\psi _4^{{ R}} (.)=( {\underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_1 \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_1 \underline{{ \mu }}{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} }) \end{aligned}$$
(81)

(ii) For \({ R}_{{ c}}\)=2, (72) can be formulated as:

$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}} =2} {\underline{{ f}}^{{ j}}+\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}}}}\right) \nonumber \\&+\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}} =2} {\underline{{ f}}^{{ j}}\overline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}\overline{{ c}}_{{ j}}}}}\right) \end{aligned}$$
(82)
$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })( {\underline{{{ f}}}^1}+{\underline{{ f}}^2}+\overline{{{ f}}^3} +\overline{{{ f}}^4})\nonumber \\&+( {\overline{{ c}}_1 \underline{{{ f}}^1}+\overline{{ c}}_2 {\underline{{ f}}^2} + \overline{{ c}}_3 \overline{{{ f}}^3} +\overline{{ c}}_4 \overline{{{ f}}^4} }) \end{aligned}$$
(83)
$$\begin{aligned}&0=\underline{{{ f}}^1}\left( {1}+\overline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) +{\underline{{ f}}^2}\left( {1} +\overline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) + \cdots \nonumber \\&\quad \cdots + \overline{{{ f}}^3} \left( {1} +\overline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) +\overline{{{ f}}^4} \left( {1} +\overline{{ c}}_4 ({-{{ y}}_{\mathrm{des}} -\gamma })\right) \nonumber \\ \end{aligned}$$
(84)

Replacing total interval firing set (73) into (84)

$$\begin{aligned} 0= & {} ( {\underline{{ \mu }}{\tilde{ A}}_{1}^{1} \underline{\mu }\tilde{{ B}}})_1^{1} ( {1}+\overline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} -\gamma }))\nonumber \\&+\,( {\underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} \underline{{ \mu }}\tilde{{ B}}_{1}^{2} })( {1} +\overline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} -\gamma }))+ \cdots \nonumber \\&\cdots + ( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{1} })( {1} +\overline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} -\gamma }))\nonumber \\&+\,{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} \overline{\mu }\tilde{{ B}}_{1}^{2} ( {1} +\overline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} -\gamma })) \end{aligned}$$
(85)

Reformulating (85)

$$\begin{aligned} 0= & {} ( {{\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} }){\overline{\mu }} \tilde{{ B}}_1^1\nonumber \\&+( {{\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_4 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_4 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} }){\overline{\mu }} \tilde{{ B}}_1^2 +\cdots \nonumber \\&\cdots +( {\underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_{2} \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_{2} \underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} {{ y}}_{\mathrm{des}} })\underline{{ \mu }}\tilde{{ B}}_{1}^{2}\nonumber \\&+( {\underline{{ \mu }}\tilde{{ A}}_{1}^{1} -\overline{{ c}}_1 \gamma \underline{{ \mu }}\tilde{{ A}}_1^1 -\overline{{ c}}_{1} \underline{{ \mu }}{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} })\underline{{ \mu }}\tilde{{ B}}_{1}^{1} \end{aligned}$$
(86)

Then the following expression is obtained:

$$\begin{aligned} \psi _1^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 +\psi _2^{{ R}} (.){\overline{\mu }} \tilde{{ B}}_1^2 +\psi _3^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^2 +\psi _4^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_1^1 =0\nonumber \\ \end{aligned}$$
(87)

where

$$\begin{aligned}&\psi _1^{{ R}} (.)=( {{\overline{\mu }} {\tilde{{ A}}}}_1^2 -\overline{{ c}}_3 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_3 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} ) \nonumber \\&\psi _2^{{ R}} (.)=( {{\overline{\mu }} {\tilde{{ A}}}}_1^2 -\overline{{ c}}_4 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_4 {\overline{\mu }} {\tilde{{ A}}}_1^2 {{ y}}_{\mathrm{des}} ) \nonumber \\&\psi _3^{{ R}} (.)=( {\underline{\mu }{\tilde{{ A}}}}_1^1 -\overline{{ c}}_2 \gamma \underline{\mu }{\tilde{{ A}}}_1^1 -\overline{{ c}}_2 \underline{\mu }{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} ) \nonumber \\&\psi _4^{{ R}} (.)=( {\underline{\mu }{\tilde{{ A}}}}_1^1 -\overline{{ c}}_1 \gamma \underline{\mu }{\tilde{{ A}}}_1^1 -\overline{{ c}}_1 \underline{\mu }{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} ) \end{aligned}$$
(88)

(iii) For \({{ R}}_{{ c}}=3\), (72) can be formulated as:

$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })\left( {\sum \limits _{{{ j}}=1}^{{{ R}}_{{ c}} =3} {\underline{{ f}}^{{ j}}+\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}} } }\right) \nonumber \\&\quad +\,\left( {\sum \limits _{{{ j}}={1}}^{{{ R}}_{{ c}} =3} {\underline{{ f}}^{{ j}}\overline{{ c}}_{{ j}} +\sum \limits _{{{ j}}={{ R}}_{{ c}} +1}^{{ N}} {\overline{{ f}}^{{ j}}\overline{{ c}}_{{ j}}}}}\right) \end{aligned}$$
(89)
$$\begin{aligned} 0= & {} -( {{{ y}}_{\mathrm{des}} +\gamma })( \underline{{{ f}}^{1}}+\underline{{{ f}}^{2}}+\underline{{{ f}}^{3}}+\overline{{{ f}}^{4}} )\nonumber \\&\quad +( {\overline{{ c}}_1 \underline{{{ f}}^1}+\overline{{ c}}_{2} {\underline{{ f}}^{2}} + \overline{{ c}}_{3} {\underline{{{ f}}}^{3}}+\overline{{ c}}_{4} \overline{{{ f}}^{4}} }) \end{aligned}$$
(90)
$$\begin{aligned}&0=\underline{{{ f}}^1}( {1}+\overline{{ c}}_1 ( {-{{ y}}_{\mathrm{des}} -\gamma }))+{\underline{{ f}}^2}( {1} +\overline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} -\gamma }))+ \cdots \nonumber \\&\quad \cdots + {\underline{{ f}}^{3}}( {1} +\overline{{ c}}_3 ( {-{{ y}}_{\mathrm{des}} -\gamma }))+\overline{{{ f}}^{4}} ( {1} +\overline{{ c}}_{4} ( {-{{ y}}_{\mathrm{des}} -\gamma }))\nonumber \\ \end{aligned}$$
(91)

Replacing total interval firing set (73) into (91)

$$\begin{aligned} 0= & {} ( {\underline{\mu }{\tilde{ A}}_{1}^{1} \underline{\mu }\tilde{{ B}}_1^{1} })\left( {1}+\overline{{ c}}_1 ( {-{ y}_{\mathrm{des}} -\gamma })\right) +( {\underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} \underline{{ \mu }}\tilde{{ B}}_{1}^{2} })\nonumber \\&\left( {1} +\overline{{ c}}_2 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) + \cdots \nonumber \\&\cdots + ( {\underline{\mu }{\tilde{{ A}}}_{1}^{2} \underline{\mu }\tilde{{ B}}_{1}^{1} })\left( {1} +\overline{{ c}}_3 ( {-{ y}_{\mathrm{des}} -\gamma })\right) +( {{\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {\overline{\mu }} \tilde{{ B}}_{1}^{2} })\nonumber \\&\quad \left( {1} +\overline{{ c}}_4 ( {-{{ y}}_{\mathrm{des}} -\gamma })\right) \end{aligned}$$
(92)

Reformulating (92)

$$\begin{aligned} 0= & {} ( 0){\overline{\mu }} \tilde{{ B}}_{1}^{1} +( {{\overline{\mu }} \tilde{{ A}}_{1}^{2} -\overline{{ c}}_{4} \gamma {\overline{\mu }} \tilde{{ A}}_{1}^{2} -\overline{{ c}}_{4} {\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {{ y}}_{\mathrm{des}} }){\overline{\mu }} \tilde{{ B}}_{1}^{2} +\cdots \nonumber \\&\quad \cdots +( {\underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_2 \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_2 \underline{{ \mu }}{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} })\underline{{ \mu }}\tilde{{ B}}_1^2 +\cdots \nonumber \\&\quad \cdots +(\underline{{ \mu }}{\tilde{{ A}}}_1^1 +\underline{\mu }{\tilde{{ A}}}_1^2 -\overline{{ c}}_1 \gamma \underline{\mu }{\tilde{{ A}}}_1^1 -\overline{{ c}}_3 \gamma \underline{\mu }{\tilde{{ A}}}_1^2 -\overline{{ c}}_1 \underline{{ \mu }}\tilde{{ A}}_1^1 {{ y}}_{\mathrm{des}}\nonumber \\&\quad \qquad -\overline{{ c}}_3 \underline{\mu }{\tilde{{ A}}}_1^3 {{ y}}_{\mathrm{des}})\underline{\mu }\tilde{{ B}}_1^1 \end{aligned}$$
(93)

Then the following expression is obtained:

$$\begin{aligned} \psi _{1}^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_{1}^{1} +\psi _{2}^{{ R}} (.){\overline{\mu }} \tilde{{ B}}_{1}^{2} +\psi _{3}^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_{1}^{2} +\psi _4^{{ R}} (.)\underline{{ \mu }}\tilde{{ B}}_{1}^{1} =0\nonumber \\ \end{aligned}$$
(94)

where

$$\begin{aligned} \psi _1^{{ R}} (.)&=( 0) \nonumber \\ \psi _2^{{ R}} (.)&=( {{\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_4 \gamma {\overline{\mu }} {\tilde{{ A}}}_1^2 -\overline{{ c}}_{4} {\overline{\mu }} {\tilde{{ A}}}_{1}^{2} {{ y}}_{\mathrm{des}} }) \nonumber \\ \psi _{3}^{{ R}} (.)&=( {\underline{\mu }{\tilde{{ A}}}_{1}^{1} -\overline{{ c}}_2 \gamma \underline{\mu }{\tilde{{ A}}}_{1}^{1} -\overline{{ c}}_{2} \underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} {{ y}}_{\mathrm{des}} }) \nonumber \\ \psi _{4}^{{ R}} (.)&=(\underline{{ \mu }}{\tilde{{ A}}}_{1}^{1} +\underline{{ \mu }}{\tilde{{ A}}}_1^2 -\overline{{ c}}_{1} \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^1 -\overline{{ c}}_{3} \gamma \underline{{ \mu }}{\tilde{{ A}}}_1^2\nonumber \\&\qquad -\overline{{ c}}_{1} \underline{{ \mu }}{\tilde{{ A}}}_1^1 {{ y}}_{\mathrm{des}} -\overline{{ c}}_3 \underline{{ \mu }}{\tilde{{ A}}}_1^3 {{ y}}_{\mathrm{des}}) \end{aligned}$$
(95)

As it has been shown above, (72) can be represented in form given in (74) for each possible value of \({ R}_{{ c}} ( { R}_{ c} \in \left\{ {1,2,3} \right\} )\).

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kumbasar, T., Eksin, I., Guzelkaya, M. et al. An inverse controller design method for interval type-2 fuzzy models. Soft Comput 21, 2665–2686 (2017). https://doi.org/10.1007/s00500-015-1966-0

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00500-015-1966-0

Keywords

Navigation