Minimizing Energy Cost in Multi-Legged Walking Machines

Abstract

Due to their ability to avoid obstacles and to move over difficult terrain, moreover having the ability to adjust their posture, walking machines for many years have been considered as very promising devices for inspection, exploration and surveyance tasks, however still they have not been widely applied. One of the main limitations is the power supply. Six legged walking machines are robust from the point of view of their walking stability in difficult terrain, but their actuators (18 if each leg has active 3 DOF's) adds to their weight what increases the energy consumption. The higher energy consumption requires more efficient batteries, but usually those are heavier, what again increases the energy demand. Therefore at the design stage a detailed analysis is required of how to decrease the energy consumption. This paper studies energy consumption considering the tripod gait of hexapods. The method used for energy evaluation is presented and the results are discussed. The discussion of energy saving both for the leg transfer phase and during the support phase, which is the most demanding phase, is presented. The energy consumption is expressed in the normalized form, depending on the normalized leg proportions, body height and step length. The straight line forward/backward and side walking are analyzed. The aim of the studies is to provide to the designers the information about favorable leg proportions taking into account the reduction of required energy and to provide the information which leg posture should be selected.

Power Consumption Characteristics Research on Mobile System of Electrically Driven Large-Load-Ratio Six-Legged Robot

“…Hence, the simplified power consumption model of robot mobile system can be written when the robot walks from the initial attitudes under the mixed-type II or ant-type tripod gait, the initial attitudes of abductor joints are △θ 1 =△θ 3 =△θ 4 =△θ 6 =60º and △θ 2 =△θ 5 =0º, and the legs 2, 4, and 6 are in the support phase. Then The tangential force 30), (32), and (34). The mathematical expressions the foot forces can be obtained for the legs 2, 4, and 6.…”

“…The energy loss assessment was executed by the experiments of robot. Zielinska [31,32] discussed the poses of support legs and the relation between link proportions and power consumption when the legged robots linearly walked along the horizontal/ inclined plane. Lin and Song [33] analyzed the relation between walking speeds and power consumption of system for a pantograph quadruped robot.…”

Advanced motions for hexapods

“…13 –15 Pragmatic approaches may, for example, base design decisions on the characteristics of the target deployment environment 14 or on the torque limitations of the intended actuators. 16 Optimization-based strategies may consider energy consumption, 17 mobility 18 or dexterity 19 as the optimization metric.…”

“…where τ i ∈ ℜ 2 , bold-italicJ i ∈ ℜ 2 × 2 and bold-italicF i ∈ ℜ 2 are the i th leg’s joint torque, Jacobian and contact force, respectively. The total energy cost, E ∈ ℜ , is the power integrated over the motion sequences, 17 which for the discretized case is…”

Power Consumption Characteristics Research on Mobile System of Electrically Driven Large-Load-Ratio Six-Legged Robot

“…The energy loss assessment was executed by the experiments of robot. Zielinska [31,32] discussed the poses of support legs and the relation between link proportions and power consumption when the legged robots linearly walked along the horizontal/ inclined plane. Lin and Song [33] analyzed the relation between walking speeds and power consumption of system for a pantograph quadruped robot.…”