Control of a Self-Balancing Two-Wheeled Cargo Transport Robot with Separation-Combination Capability

The Single Inverted Pendulum (SIP) model is widely employed in various robotics applications for balance control due to its structural simplicity and ease of implementation. Self-balancing two-wheeled transport robots offer the advantage of maintaining stability while enabling dynamic acceleration and deceleration. However, their performance is limited when carrying heavy loads, and maintaining stable balance during the loading process remains challenging. To address these limitations, this study proposes a control strategy for a pair of self-balancing two-wheeled transport robots that operate cooperatively through a separation–combination mechanism. Simulations were conducted to compare the performance of the Linear Quadratic Regulator (LQR) and Model Predictive Control (MPC) under a self-balancing condition with an external force of 100 N applied. Additionally, the proposed separation–combination method was evaluated through a simulation involving the transfer of a 20 kg delivery module. The results showed that both methods could stably transport the load, while the MPC-based approach reduced the wheel torque by approximately 50% compared to the LQR method. These findings indicate that a two-wheeled robot employing MPC in conjunction with the separation–combination method is well-suited for transporting heavy loads.