To reduce the workload of farmers in transporting agricultural products, transport robots have been deployed in agricultural fields. However, maintaining the stability of transported goods on inclined or uneven ground remains a challenge. To address this issue, we introduced a balance control system based on a 3-RPS (Revolute-Prismatic-Spherical) parallel mechanism to ensure cargo stability. We used ADAMS and Matlab Simulink for joint simulation. Through ADAMS, we established the kinematic model of the 3-RPS parallel mechanism and input parameters, such as the current angle and height of the platform, into Matlab Simulink. After computing the kinematic inverse solution of the 3-RPS parallel mechanism, we employed a PID (Proportional-Integral-Derivative) controller to ensure precise control, successfully simulating the maintenance of balance by the 3-RPS parallel system during motion. To validate our approach, we installed an IMU (Inertial Measurement Unit) on the cargo platform of a mobile robot to collect data on platform angle variations and tested the balance control system on sloped agricultural roads. The balance control system reduced the pitch angle of the cargo platform from 11.53° to 1.09° on a continuous uphill road and from 14.13° to 2.85° on a bumpy and downhill road....