基於力控制之輪腳複合機器人動態步態生成

Dynamic Gait Generation for a Leg-Wheel Transformable Robot Based on Force Control

林筠萌(Yun-Meng Lin)

指導教授 ： 林沛群

國立臺灣大學/工學院/機械工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201702396

摘要

多足機器人由於具有穩定行走及優越的越障能力等特色，在機器人界是ㄧ項熱門的研究主題，其中力控制策略為各研究團隊近幾年來特別著重的項目，因力控制比起位置控制能夠有較高的誤差容忍度，能夠使運動更加強健。
本研究目的在於為實驗室第二代輪腳複合機器人TurboQuad開發合適的動態步態行為並檢視其各項運動表現。本研究所採用的動態行為開發策略為model-based控制方法，所選用的模型為SLIP (spring-loaded inverted pendulum)模型。首先以一外力估測模型估測外力並以力控制方式使機器人雙自由度輪腳中的徑向自由度表現出如同被動彈簧般的效果，以模擬SLIP模型中的彈簧表現。同時探討適合機器人運作之狀態參數，為其開發能夠快速運動的動態行為如小跑步態(trotting)及彈跳步態(pronking)。接著探討SLIP中各參數對軌跡之影響以作為選擇軌跡的參考，並探討機器人在兩穩定操作點間轉移的可能性。除此之外，本研究同時利用電流控制的方式為TurboQuad開發出垂直跳之能力，提供另一種力控制的可能性。
本研究保留TurboQuad原先之中樞模式產生器控制架構(Central Pattern Generator, CPG)，以維持其輪腳變換之能力。同時將CPG架構與model-based control兩種控制方法結合，並升級機電系統使其足以負荷機器人豐富的各項行為表現。本研究也規劃了機器人在轉向時之軌跡，以差速設計減少打滑現象。並對機器人之各項運動表現以定性或定量實驗方法進行評估，如運動時的能量效率、越障能力、運動穩定度，探討其優勢及限制，以供之後改版設計參考。

關鍵字

仿生機器人 ； 四足機器人 ； 動態步態 ； 模型基礎控制 ； 力控制 ； 電流控制

並列摘要

Multi-legged robots are one of the most popular topics in robotics owing to their ability to move stably and their superior obstacle negotiation. In recent years, most research teams have put their emphasis on force control strategies because they allow the robot to tolerate greater error compared to position control, and therefore make the motion more robust. The purpose of this thesis is to develop dynamic gaits for a leg-wheel transformable robot, TurboQuad, and evaluate its motion performance. Model-based control is used and the SLIP (spring-loaded inverted pendulum) model is chosen. A force control method is developed to make the translational degree of freedom of the leg-wheel perform spring-like motion to match the spring in the SLIP model. Parameters of the SLIP model that suit the robot are searched for, to initiate dynamic gaits such as trotting and pronking. Then the effects of these parameters are discussed to build the basis for choosing suitable trajectories. The ability to transition between two stable operation points is also developed. Besides, hopping behavior is accomplished by current control.
The original control structure of TurboQuad is preserved (i.e. Central Pattern Generator) and combined with model-based control. The mechatronic system is upgraded to meet the requirements for the robot to perform versatile behaviors. A turning strategy is developed and differential steering is used to reduce slippage. The performance of the robot in terms of energy efficiency, obstacle negotiation ability and motion smoothness are also evaluated.

並列關鍵字

bio-inspired robot ； quadruped robot ； dynamic gaits ； model-based control ； force control ； current control

參考文獻

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