Robots have recently graduated from structured laboratories to outdoor environments with varying and unstructured terrain. In order to be highly mobile and effective in these settings, robotics research will need to address 1) the underlying physics of robot/terrain interaction and 2) design methodologies for creating mechanically robust robots capable of multiple modes of locomotion.
Our research approaches these issues by focusing on bio-inspired design and increasing the mobility, agility, and versatility of robots and dynamic systems in the context of challenging terrains. In terms of biologically-inspired design, we work on:
- perching micro air vehicles that can both fly and locomote on arbitrary surfaces and
- the design of active camouflage systems based on cephalopod morphology.
Furthermore, we are concerned with creating more agile vehicles by studying:
- longitudinal load transfer in non-holonomic Unmanned Ground Vehicles (UGVs) and
- the design and control of omnidirectional UGVs in rough terrain.
|Vehicle-Terrain Interaction Modeling - Terramechanics, the study of vehicle-terrain interaction, has been used for decades to model and predict off-road vehicle mobility performance on deformable terrains. We are currently investigating the accuracy of terramechanics models when applied to small-wheeled vehicles. The lab has introduced two new pressure-sinkage models which have been shown to significantly improve the accuracy of traction models for these vehicles. Current lab facilities for this research include a vehicle terrain testbed, geotechnical soil testing equipment (in the civil engineering dept.),simulation software and a pressure-sinkage testbed. We are now developing a fluidized testbed to investigate the effect of soil volume fraction of mobility metrics.|
|Perched Landing of Micro Air Vehicles - We are interested in the design of mechanical attachment mechanisms that give micro air vehicles the ability to land on arbitrary surfaces. Additionally, we are investigating methodologies that give UGVs the ability to locomote in different domains(land, vertical surfaces, air) without resorting to "Swiss-Army Knife" design. This work is supported by the Office of Naval Research.|
|HyTAQ Robot(Hybrid Terrestrial and Aerial Quadrotor) - The HyTAQ is a novel mobile robot capable of both aerial and terrestrial locomotion. Flight is achieved through a quadrotor configuration; four actuators provide the required thrust. Adding a rolling cage to the quadrotor makes terrestrial locomotion possible using the same actuator set and control system. Thus, neither the mass nor the system complexity is increased by inclusion of separate actuators for terrestrial and aerial locomotion.|
During terrestrial locomotion, the robot only needs to overcome rolling resistance and consumes much less energy compared to the aerial mode. This solves one of the most vexing problems of quadrotors and rotorcraft in general — their short operation time. Experimental results show that the hybrid robot can travel a distance 4 times greater and operate almost 6 times longer than an aerial only system. It also solves one of the most challenging problems in terrestrial robot design — obstacle avoidance. When an obstacle is encountered, the system simply flies over it.
|Omnidirectional Vehicles for Rough Terrain - We are investigating mechanical design and control algorithms for omnidirectional vehicles capable of operating in real-world environments. Typical omnidirectional vehicle designs are only suitable for clean, smooth surfaces due to their use of specialized wheels. In contrast, our design is based on the ''active split offset castor'. This design utilizes standard wheels, which gives it a high load carrying capacity and robustness to dirt and debris. It also has a high kinematic isotropy and low scrubbing torque when compared to other omnidirectional vehicle designs that employ conventional wheels. We are working on this project in collaboration with the Robotic Mobility Group at MIT and the work is supported by the Army Research Office.|
Video is available on youtube:
|Agile Non-holonomic Vehicles with Variable Internal Inertial Properties - This research focuses on creating a novel class of highly agile UGVs capable of controlling their internal mass and inertial properties during locomotion. The UGVs will be able to longitudinally adjust their center of mass location. This will allow for direct control of the normal force acting on the front and rear wheels. Controlling this force will give the UGV the ability to execute dynamic maneuvers including sharp turns and controlled sliding, stabilize itself to recover from unwanted sideslip, and traverse a larger set of obstacles (by unloading the suspension when the wheels cross the hazard).|