基於足部力追蹤控制之輪足複合式四足機器人 全機控制架構開發

Abstract

實驗室第三代輪足複合機器人，結合「輪」於平坦地形高效移動的特性，以及「足」式機器人能於崎嶇地形移動的特性，使機器人在兼顧運動能量效率的同時，於各類崎嶇地形運動。 本研究基於實驗室第三代輪足複合機器人，期望達成輪足機器人能以足模式能夠穩定平穩行走的最終成果。於此研究中，針對第三代輪足機構，提出輪足機構的簡化動力學模型，使得能以更簡單、快速的方式求解輪足模組於空中運動時，對於機身所造成的慣性力影響及運動所需的馬達扭矩。 結合生物軀幹對於接觸力控制的概念，針對輪足模組提出力追蹤控制器架構，以導納控制為基礎，透過自適應彈簧阻尼系統之剛性，使輪足模組於行走過程之中，能夠足尖點的地面接觸力進行控制。 本研究針對輪足機器人之行走步態提出新一代全機控制架構，整合來自機身狀態估測器的資訊，分別對於滯空腳及觸地腳提出新的控制方法，以貝茲曲線規劃滯空腳軌跡；以全機力分布控制器分配觸地腳之地面接觸力，以全機狀態補償器補償機身當前位置、姿態，並以輪足力追蹤控制器進行控制。 最終，本研究以模擬及實體實驗驗證全機狀態控制器的控制成效，新一代全機控制架構可以有效減少機器人行走時地面之衝擊力，使得行走步態之穩定性有顯著改善。

The third-generation wheel-legged robot developed by our laboratory combines the efficient movement characteristics of ”wheels” on flat terrain with the ability of ”legged” robots to navigate rough terrain. This combination allows the robot to maintain energy efficiency while moving across various terrains. This research aims to achieve the ultimate goal of enabling the wheel-legged robot to walk stably and smoothly in leg mode, based on the third-generation wheel-legged robot. In this study, a simplified dynamic model of the wheel-legged mechanism is proposed, allowing for a more straightforward and faster solution to the inertial forces affecting the robot body and the motor torques required for movement during swing phase motion. Incorporating the concept of contact force control from biological structures, a force-tracking controller framework for the wheel-legged module is proposed. Based on admittance control, the rigidity of the adaptive spring-damping system is used to control the ground contact force at the toe points during the walking process. This research proposes a new generation of Whole-Body Control architecture for the walking gait of the wheel-legged robot. It integrates information from the body state estimator and proposes new control methods for both the swing and stance legs. The swing leg trajectory is planned using Bezier curves, while the ground contact forces of the stance legs are distributed using a whole-body force distribution controller. The body position and posture are compensated using a whole-body position compensator, and control is executed through the wheel-legged force-tracking controller. Finally, the effectiveness of the Whole-Body Control architecture is verified through simulations and physical experiments. The new generation of Whole-Body Control architecture can significantly reduce the impact of ground reaction forces generated by the swing leg during walking, leading to a noticeable improvement in gait stability.