We present admittance control and fingertip contact detection with a linkage gripper remotely driven by a pneumatic rolling diaphragm actuator. The gripper is driven by underactuated mechanisms sensorized by joint encoders in order to fully determine the gripper state. We present the modelling of the linkage and fluidic transmission, validate its ability to regulate pinch force via admittance control within an RMS error well under 0.5 Newtons, and show the ability to detect contact at targeted locations on the linkage. In addition, we demonstrate simple grasping behaviors: blindly searching for an unobstructed object and detecting object loss. Our results show that an integrative approach of instrumenting underactuated gripper mechanisms can result in a lightweight gripper that is not only mechanically adaptive but sensitive enough to react to contact events without distal sensors or vision.

A dynamic model of a jump glider is presented and correlated with the results obtained with a prototype glider. The glider uses a carbon fiber spring and a main wing that pivots approximately parallel to the airflow during ascent and latches into place for a gliding descent. The robot demonstrates longer traveled distance than an equivalent drag-free ballistic mass. A detailed numerical and a simplified algebraic model are also introduced, which are useful for exploring design tradeoffs and performance. These models suggest ways to improve the traveled distance and indicate that with modest variations in the wing angle of attack during ascent, one can choose from a variety of launch angles to accommodate variations in ground friction without greatly compromising range.

Control of insect-scale flapping-wing robots is challenging due to weight constraints and inherent instabilities. Instead of adding more actuators to increase the controllability of the flapping-wing robot, we use a single actuator to drive a system of mechanical linkages to cause bilaterally asymmetric changes in the wing hinge spring rest angle of the left and right wings. We show in simulation that such a control input can generate wing motions which produce yaw and roll torques. A kinematic model of the mechanism was developed and an at-scale prototype of this concept was built. High speed videos of its wing motions are consistent with the kinematic model and according to the simulation, are capable of generating adequate yaw and roll torques for attitude control.

The Harvard RoboBee is the first insect-scale cflapping-wing robot weighing less than 100 mg that is able to lift its own weight. However, when flown without guide wires, this vehicle quickly tumbles after takeoff because of instability in its dynamics. Here, we show that by adding aerodynamic dampers, we can can alter the vehicle's dynamics to stabilize its upright orientation. We provide an analysis using wind tunnel experiments and a dynamic model. We demonstrate stable vertical takeoff, and using a marker-based external camera tracking system, hovering altitude control in an active feedback loop. These results provide a stable platform for both system dynamics characterization and unconstrained active maneuvers of the vehicle and represent the first known hovering demonstration of an insect-scale flapping-wing robot.