Tham khảo tài liệu 'humanoid robots part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Performance Assessment of a 3 DOF Differential Based Waist joint for the iCub Baby Humanoid Robot 93 Due to mechanical limitations it can be observed from Figure 14 that the robot waist was not able to follow the reference signal accurately at rates of change higher than 2 rad s even when setting the speed limit at its maximum. 7. System experimental results The following results were obtained by collecting measurements from the real system through the microcontroller TMS320F2810 DSP from Texas Instruments on which the control system was implemented through its JTAG interface to a PC. Figure 15-17 show the results for the position control when a step input is presented with a set speed of 84 deg s in the joint. The joint is set to move forward and backwards between 22 and 65 deg. After evaluating the results from the real system different factors not considered in the simulation model like friction in the waist joints were observed to have little effect on the results. Fig. 15. Position Tracking Response of the real system. Fig. 16. Position tracking error of the real system. Fig. 17. Position tracking error in steady state. Actual results show errors under in steady state with overshoot. system. Reference signal in solid line actual waist speed in dashed line. 80 Speed tracking error -i-i-i- 012345678 Time sec Fig. 19. Speed tracking error of the real system. Errors under 1 deg s can be observed. 8. Conclusions and future work This work presented the design of a differential based mechanism developed to form the waist joint of a baby humanoid robot. A cascade PID based position and speed controller was developed and its characteristics such as overshoot settling time and steady state error have been evaluated through both experimentation and simulation. A control system consisting on a PID controller was established to achieve accurate position control of the joints. It has been demonstrated through experimental implementation that the
