农业工程学报
農業工程學報
농업공정학보
2013年
16期
31-41
,共11页
牛雪梅%高国琴%刘辛军%鲍智达
牛雪梅%高國琴%劉辛軍%鮑智達
우설매%고국금%류신군%포지체
机器人%机构%动力学%并联%冗余驱动%简化策略
機器人%機構%動力學%併聯%冗餘驅動%簡化策略
궤기인%궤구%동역학%병련%용여구동%간화책략
robots%mechanisms%dynamics%parallel%redundant actuation%simplified strategy
对于农业机器人而言，其动力学模型是进行动力学特性分析的基础，是实现动力学优化设计及高精度操作的前提。该文针对一种新型驱动冗余并联机构进行了动力学建模，该机构的动平台通过2个PRRR支链和1个PPRR支链与静平台相连，拥有2个转动自由度和1个平动自由度。在分析并联机构组成的基础上，充分考虑各构件惯性力的影响，建立基于Lagrange方程的工作空间完整动力学模型，并运用最小2范数法实现驱动力优化；通过分析给定路径下并联机构各主要组成构件对驱动力的影响，提出针对上述完整动力学模型的简化方案。结合并联机构应用特点，进行了仿真及试验。结果表明，非冗余驱动情况下第1，2轴向驱动力的最大值为15 N，施加冗余驱动后，最大值降为10 N，各驱动力峰值降低约33%；机构位姿角β达到57.6460o时，各驱动力均发生急剧变化，经验证可知该点为奇异点，在实际应用中应避开该点。机构末端轨迹跟踪结果显示，在 Y，Z 和β方向的最大跟踪误差分别为0.8 mm，0.6 mm和0.068o，因此，基于本文所建立的简化动力学模型的机器人控制系统具有良好的跟踪特性。该研究可为冗余并联机构的动力学控制方法设计提供重要参考。
對于農業機器人而言，其動力學模型是進行動力學特性分析的基礎，是實現動力學優化設計及高精度操作的前提。該文針對一種新型驅動冗餘併聯機構進行瞭動力學建模，該機構的動平檯通過2箇PRRR支鏈和1箇PPRR支鏈與靜平檯相連，擁有2箇轉動自由度和1箇平動自由度。在分析併聯機構組成的基礎上，充分攷慮各構件慣性力的影響，建立基于Lagrange方程的工作空間完整動力學模型，併運用最小2範數法實現驅動力優化；通過分析給定路徑下併聯機構各主要組成構件對驅動力的影響，提齣針對上述完整動力學模型的簡化方案。結閤併聯機構應用特點，進行瞭倣真及試驗。結果錶明，非冗餘驅動情況下第1，2軸嚮驅動力的最大值為15 N，施加冗餘驅動後，最大值降為10 N，各驅動力峰值降低約33%；機構位姿角β達到57.6460o時，各驅動力均髮生急劇變化，經驗證可知該點為奇異點，在實際應用中應避開該點。機構末耑軌跡跟蹤結果顯示，在 Y，Z 和β方嚮的最大跟蹤誤差分彆為0.8 mm，0.6 mm和0.068o，因此，基于本文所建立的簡化動力學模型的機器人控製繫統具有良好的跟蹤特性。該研究可為冗餘併聯機構的動力學控製方法設計提供重要參攷。
대우농업궤기인이언，기동역학모형시진행동역학특성분석적기출，시실현동역학우화설계급고정도조작적전제。해문침대일충신형구동용여병련궤구진행료동역학건모，해궤구적동평태통과2개PRRR지련화1개PPRR지련여정평태상련，옹유2개전동자유도화1개평동자유도。재분석병련궤구조성적기출상，충분고필각구건관성력적영향，건립기우Lagrange방정적공작공간완정동역학모형，병운용최소2범수법실현구동력우화；통과분석급정로경하병련궤구각주요조성구건대구동력적영향，제출침대상술완정동역학모형적간화방안。결합병련궤구응용특점，진행료방진급시험。결과표명，비용여구동정황하제1，2축향구동력적최대치위15 N，시가용여구동후，최대치강위10 N，각구동력봉치강저약33%；궤구위자각β체도57.6460o시，각구동력균발생급극변화，경험증가지해점위기이점，재실제응용중응피개해점。궤구말단궤적근종결과현시，재 Y，Z 화β방향적최대근종오차분별위0.8 mm，0.6 mm화0.068o，인차，기우본문소건립적간화동역학모형적궤기인공제계통구유량호적근종특성。해연구가위용여병련궤구적동역학공제방법설계제공중요삼고。
Dynamics modeling plays an important role in the application of agricultural robots, which is the key to analyze the dynamic characteristics and achieve high-precision operation. This paper addressed the issue of deriving the dynamic formulation of a novel 3-DOF redundantly actuated parallel mechanism. The structure of the parallel mechanism is composed of a moving platform attached to a fixed platform through two identical PRRR kinematic chains and one PPRR chain. The parallel mechanism has two translational degrees and one rotational degree. Firstly, inverse kinematic solution of the parallel mechanism was studied by analyzing the structure property and the constraint equation; Secondly, according to the kinematics of the redundant mechanism and considering fully the impact of inertial force for each component, the inverse dynamic equation was formulated in the task space by using the Lagrangian formalism, and the driving force was optimized by utilizing the minimal 2-norm method. By investigating the contribution of each term in the dynamic model to the driving force, a simplified strategy of the dynamic model for real-time control application was proposed. Simulation and experimental results showed that the maximal value of the driving force for the parallel mechanism without actuation redundancy was 15N, but that of mechanism with actuation redundancy was 10N andthe driving force peak was reduced by 33%. It is noted that the pointβ=57.6460° was the singularity which should be avoided in practical application. Additionally, the maximal tracking errors for the end-effector were 0.8mm, 0.6mm and 0.068° in Y, Z andβdirection, respectively. Thus the parallel mechanism system based on the proposed dynamic model can achieve good tracking performance. This research provides technology reference for further study of high precision real-time control of parallel mechanism.
