Mobile Robots - Moving Intelligence Part 9

Tham khảo tài liệu 'mobile robots - moving intelligence part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Mechanism and Control of Anthropomorphic Biped Robots 311 Parts Length mm Height 1840 Width 706 Depth 533 Between foot and ankle 142 Between ankle and knee 300 Between knee and hip 353 Between hip and waist 176 Between waist and neck 537 Between neck and head 332 Upper arm 263 Lower arm 247 Table 3. Segment length of WABIAN-RII. a Pitch s movable angle b Roll s movable angle c Yaw s movable angle Fig. 4. Movable range of WABIAN-RII. 312 Mobile Robots moving intelligence Fig. 5. Control system of WABIAN-RII. 3. Locomotion Pattern Generation A biped locomotion phase can be classified into a contact a single and a double supporting phase to generate a leg motion. During the single supporting phase one foot is not constrained to the ground but the other foot is on the ground. As soon as the heel of the swinging foot reaches the ground the single supporting phase is changed to the contact phase. If the toe and heel of the swinging foot contacts on the ground the phase becomes a double supporting phase. Fig. 6 shows a locomotion phase for a leg pattern generation. The smooth motion of the foot according to terrain conditions Xf can be generated by using a sixth degree polynomial considering the angle the angular velocity the angular acceleration and the height from the ground to the foot Lim et al. 2004b . Three constraints of the foot position and orientation come from the selection of initial and final values 1 where to tm and tf are the initial intermediate and final time of a step respectively. The position and orientation of the foot have an additional four constraints that are the zero initial and final velocity and acceleration x o 0 0 i fo 0 0. The sixth order polynomial for a foot motion is written as follows X 0 a0 4- alt a2 2 a3 3 4 a4 4 4 a5 5 4 a6 6 and the velocity and acceleration along the path are clearly Xf t a J 4- 2a2t 3ast2 4- 4a4t3 4- 5a5f4 4 6a6t5 i t 2a2 4 6a3t 4 12a4t2 4 20asf3 4 30a6t4. 2 3 4 Mechanism and Control of Anthropomorphic Biped Robots