UCLA

Delivering packages from a warehouse to the customer's front door consists of a diverse set of sub-tasks, from packing packages into a truck to organizing them based on destination and even carrying them to a doorstep. Such a variety of behaviors can often be difficult for a single robot to achieve efficiently. Numerous research papers have proposed splitting the tasks amongst specialized robots with some dedicated to robotic arm manipulation and others to wheeling packages to their destination. Recently, companies have even started to pivot to the full generalized solution of humanoid robots. Although some success has been seen with both solutions, these technologies occupy large amounts of space, often have large costs, and have significant limitations that prevent parallelization and scalability. As a result, this reduces the amount and efficiency of overall package delivery capacity.

To resolve these bottlenecks, we introduced a new robotic platformed called LIMMS, or Latching Intelligent Modular Mobility System. LIMMS is a symmetric 6 degree of freedom (DOF) modular manipulator robot with a latching mechanism and wheels at both ends. In one configuration, LIMMS can use its end effector to latch itself to designated anchor points to behave like a traditional manipulator and move boxes around. Meanwhile, by placing anchor points on the box, multiple LIMMS can attach themselves to a box to act as legs in which the box is the body to facilitate transportation across larger distances including outside of the truck. In this way, all package delivery sub-tasks are covered by the different modes LIMMS can be in. The only limiting factor to the functionality of LIMMS is the anchor points. These anchor points, sometimes referred to as latching patterns or patterns, can be as close as a few inches or even tangent to each other given the box is sturdy enough. Many more LIMMS can work together to lift heavier boxes than any humanoid robotic system could. Not only has its physical constraints been reduced, but its spatial constraints as well. When parallelizing a task, having more robots can increase efficiency. However, too many robots working together can cause congestion leading to an inefficient system. With the latching mechanism, LIMMS can use any surface with latching patterns, e.g., walls, ceilings, boxes. This increases the overall operational surface area reducing the chance for gridlocks. With all of these features, LIMMS can be used to solve a large variety of problems more efficiently that no other system can due to its design.

This manuscript aims to detail the development and research findings of LIMMS. In particular there are five major contributions. The first being the introduction of LIMMS as a platform and the prototypes designed and built. Secondly, the latches on LIMMS are designed in such a way that it admits a large region for which latching is theoretically guaranteed. This theoretical boundary exceeds existing self-aligning mechanisms. The third contribution is the use of Jacobian fields to determine trajectories in which the load at the end effector is balanced through the structure of the robots, such that the effective torque required is much lower. Fourthly, we formulate an optimization problem to generate trajectories for LIMMS to use to deliver packages. Lastly, we demonstrate LIMMS as a concept with four LIMMS connecting to a box to form a quadruped to deliver itself and then return to the truck.