本文导出空间开链型机构惯性力完全平衡的充分必要条件,提出相对平衡的概念。论证开链型空间机构中有含移动自由度的运动副时,用重新分布质量法不可能使该机构惯性力完全平衡。本文还提出把闭链型空间机构分解成开链型空间机构,并利用开链型空间机构惯性力完全平衡的方法解决闭链型空间机构惯性力的完全平衡。 In this paper, the necessary and sufficient conditions for complete balance of inertial forces of open-chain mechanism in space are derived, and the concept of relative balance is proposed. When demonstrating that there is a moving pair with freedom of movement in an open-chain space agency, it is impossible to completely balance the inertial force of the agency with the redistribution quality method. In this paper, the mechanism to decompose the closed-chain space organization into open-chain space organization and the complete balance of the inertia force of the closed-chain space organization by means of the complete balance of the inertia force of the open-chain space organization are also proposed.