**5. Conclusions**

In this chapter, three most popular reaching laws, i.e., Gao's, Utkin's, and Bartoszewicz's reaching law in relative degree one, are discussed. In addition to that state-of-the-art research in relative degree two sliding variable for Gao's is discussed. Comparison shows better performance in terms of finite time ultimate boundedness of states and reduced ultimate band of state variable in case of RD2. The concept of ultimate band, finite-time bounded stability and requirement of control effort for all the reaching laws are briefly explained. Examples are given with simulation results for all the cases which show the behavior of the closed-loop system.
