Dynamic robotic bricklaying force-position control considering mortar dynamics for enhanced consistency

Abstract

With growing construction automation needs and aging workforce, robotic bricklaying technologies offer promising solutions by replacing labor-intensive manual wall construction. Despite advances in mechatronics, trajectory generation, and adhesive bonding, bricklaying process consistency still remains a major issue, challenged by nonlinear mortar dynamics, variable thickness, and lack of force-position control. This paper enhances consistency by adjusting the robot trajectory to achieve the desirable maximum contact force and brick placement accuracy. The feedforward bricklaying trajectory is generated by solving an optimal control problem with unspecified terminal time to approach the desirable maximum force while maintaining placement accuracy, considering the identified mortar dynamics. To ensure precise positioning and robust desired maximum contact force, robotic bricklaying force-position feedback control is proposed to dynamically control the velocity utilizing real-time force feedback. Simulations and experiments validated the proposed approach, including shear tests, demonstrating enhanced consistency and the relationship between maximum contact force and bond strength.