Mechatronics Laboratory

Mechatronics Laboratory

Supported Projects/Research

Design of a Gripper/Cutting Tool End-Effector for the BIO-Plex MHS/RM:

"Tool and Interface Design of a Robotic Harvesting Adapter for the NASA JSC Biomass Production Chamber" - Martin J. Kornfeld M.S. Thesis Spring 2003

Thesis Paper (.pdf 9.814KB MB) - © Martin J. Kornfeld 2003

"Two DOF Gripper Kinematics of a Harvesting Adapter for the Robotic System used in the NASA JSC Biomass Production Chamber" - Wolfgang Ptacek M.S. Thesis Spring 2003

Thesis Paper (.pdf 15.38 MB) - © Wolfgang Ptacek 2003

Animation of Harvesting Adapter (.avi 990x700 28.861 MB) - © Wolfgang Ptacek 2003

Lab support included a custom designed Atmel AVR Based data acquisition and quad axis motion control system. Descriptions of the five 4-layer circuit boards that comprise the electronic subsystems of the Harvesting Adapter are described below.

Boards:

The microcontroller board includes an 8-bit microcontroller running at 16 MHz. It has internal hardware capable of generating six separate pulse width modulated (PWM) motor drive signals, two asynchronous serial ports, and numerous digital I/O lines for interfacing to the encoder counters, limit switches, and other control lines. The microcontroller board has two 16-bit encoder counters for tracking the jaw motor positions, four limit switch inputs for “home” indexing each of the four axes, and a RS-232 serial interface. One of the serial ports on the microcontroller is used to communicate with a force sensor board that provides signal conditioning and digitizing for the capacitive force sensors in the adapter’s jaws. The other is used for command/data uplink/downlink to a higher-level control computer system. The maximum power consumption of the processor and force sensing boards together is approximately 1 W.
The PWM amplifier board provides an electrically-segregated high-power motor-drive subsystem. All four motors are connected to the amplifier board. An interface between the amplifier board and processor board is provided to pass encoder signals and amplifier command/control signals. The amplifier board power consumption depends on the jaw and cutting blade loading. The maximum power the amplifier board can handle is approximately 30W for short duty cycles.
Two other boards were designed for limit switch mounting (due to the miniature switch size) and a third for a pogo pin interface to the end effector. The prototype boards were hand assembled using surfaced mount rework equipment. Together, the HA electronics subsystems will provide local closed-loop position control, local force control and local power control, as well as an interface for downlink/uplink with the computer systems that control the integrated adapter, end effector, robot arm, gantry system.

Photos:

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