Fuzzy Terminal Sliding Mode Control with Compound Reaching Law and Time Delay Estimation for HDU of Legged Robot

Table 6

HDU position error under different control methods.

Working condition	PID controller	FTSM		FTSM + TDE
	Maximum error (mm)	Maximum error (mm)	Improvement to PID controller (%)	Maximum error (mm)	Improvement to PID controller (%)
①	0.115	0.061	47.0	0.041	64.3
②	0.212	0.112	47.2	0.079	62.7
③	0.214	0.123	42.5	0.081	62.1
④	0.391	0.226	42.2	0.162	58.6
⑤	0.056	0.022	61.0	0.015	73.2
⑥	0.059	0.023	61.0	0.016	72.8