High order differential feedback controller design and implementation for a Stewart platform

Abstract

Stewart platform or other parallel manipulators with a Stewart structure are commonly used in flight simulators, surgical operations, medical rehabilitation processes, machine tools, industrial applications, etc. Therefore, researchers have paid attention to position control of these manipulators in addition to their design and development process. In this study, a developed Stewart platform and its inverse kinematic analysis are presented first. Then, a model-free control scheme called a high order differential feedback controller scheme is designed for the Stewart platform in order to improve its trajectory tracking performance and robustness against to different reference trajectories. Real-time trajectory tracking experiments with varied reference trajectories are carried out to show the robustness and effectiveness of the high order differential feedback controller scheme compared to the traditional proportional–integral–derivative controller of which the parameters are optimally tuned. The obtained visual trajectory tracking results and numerical performance results based on error-based performance measurement metrics such as integral of absolute error, integral of squared error, and integral of time-weighted absolute error are provided for both the proposed high order differential feedback controller scheme and the optimal tuned proportional–integral–derivative controller. Experimental results show that the proposed high order differential feedback controller scheme is more robust than the proportional–integral–derivative controller. Furthermore, the high order differential feedback controller scheme has superiority in both transient and steady-state responses and even the parameters of the proportional–integral–derivative controller are optimally tuned.

HCDRNN-NMPC: A New Approach to Design Nonlinear Model Predictive Control (NMPC) Based on the Hyper Chaotic Diagonal Recurrent Neural Network (HCDRNN)

“…As found in Figure 9, the control signal applied to link 1 provides for the limit needed for the forces exerted in each link, assuming that the positions of other links remain unchanged. (3) In the third sample path, which is similar to the path presented in the reference [33], to evaluate the performance of the proposed controller in tracking the paths with rapid changes, the following two-level step path has been examined.…”

Real-time trajectory tracking control of Stewart platform using fractional order fuzzy PID controller optimized by particle swarm algorithm

“…Referring back to Figure 1(b), the location of the i th attachment point T i on the moving platform is given in Equation (1) (Ayas et al , 2019; Bingul and Karahan, 2012). r p is the radius of the points to its center.…”

“…r p is the radius of the points to its center. In the same manner, the location of the i th attachment point B i on the fixed platform can be also gotten as given in Equation (2) (Ayas et al , 2019; Bingul and Karahan, 2012). …”

“…It was proved that the designed controller can successfully control the full load end effector with considerably more accurate tracking and also realize the desired path with acceptable and reasonable viscous jacks. Ayas et al (2019) designed a high order differential feedback controller scheme for enhancing trajectory tracking performance and robustness under different reference trajectory for the SP. Also, by using experimental results and numerical results based on integral error performance indices, the superiority of the proposed controller was illustrated comparing the PID controller.…”