Post by Admin on Jan 2, 2016 22:49:50 GMT
Subsequent to the success of CHARLI-L, the CHARLI-2 was born. Having gained extensive insight & understanding from CHARLI-L, many improvements were incorporated into the CHARLI-2 design. Of particular note is the dropping of the old designs Four-Bar Linkage in favour of synchronising 2x servo's (as before) however with both servo's pinion/output gear driving a larger 'joint-mounted' gear, this in effect doubled both servo's torque & additionally timings by 3 after the pinions on gear configuration.
Furthermore to the considerable increase of joint torque was an additional DOF, for a total of 6x DOF per each leg, allowing for a more human-like gait.
Another tremendous insight highlighted from the development of CHARLI-L was, in addition to maximising servo torque, that the torque requirements on the servo's can be reduced by way of design, insomuch Prof Hong's RoMeLa team discovered that as well as simply reducing CHARLI-2's overall weight, they would pay especial attention to the distribution/redistribution of that weight to minimise the moment of inertia, for example, the batteries were located in the thigh area and the shin's & feet were designed to be as light as possible. This resulted in the Centre Of Mass being located just beneath the hip plane, subsequently minimising the moment of inertia & reducing torque requirements from the servo's used.
Overall Height: 1410mm
Overall Width (arms ext): 1354mm
Leg Length: 775mm
Foot Width: 140mm
Weight: 12.1kg
CHARLI-2 Servo Torque: 10.5Nm
(2x per upper leg joint/1:3 gear ratio giving 63Nm)
Dynamixel EX-106+ (RS485 Asynchronous Serial)
1% (0.63Nm) servo torque per 1% (121g) overall body weight
Dims: W40.2xH65.1xD46
Servo Weight: 154g
Number of Servo's: 18 (legs only)
Leg Servo Weight: 2.77kg (legs only)
Arm Servo (x8) Weight: 0.28kg/0.5kg
(3.6Nm/6.3Nm each)
Head Servo (x2) Weight: 0.14kg (3.6Nm each)
Total Servo Weight: 3.69kg
Servo's accountable weight: 30.5%
(Note: Servo's accountable weight marginally higher than CHARLI-L due to 0.6kg weight reduction in CHARLI-2 version)
Rpm: 69.93 (@18.5V)
(Bear in mind Rpm is from EX-106+ datasheet spec, not AFTER the 1:3 geardown/ratio used on CHARLI-2 which would result in 23.3rpm)
Lower body weight: 6.8kg (53.4%)
Furthermore to the considerable increase of joint torque was an additional DOF, for a total of 6x DOF per each leg, allowing for a more human-like gait.
Another tremendous insight highlighted from the development of CHARLI-L was, in addition to maximising servo torque, that the torque requirements on the servo's can be reduced by way of design, insomuch Prof Hong's RoMeLa team discovered that as well as simply reducing CHARLI-2's overall weight, they would pay especial attention to the distribution/redistribution of that weight to minimise the moment of inertia, for example, the batteries were located in the thigh area and the shin's & feet were designed to be as light as possible. This resulted in the Centre Of Mass being located just beneath the hip plane, subsequently minimising the moment of inertia & reducing torque requirements from the servo's used.
Overall Height: 1410mm
Overall Width (arms ext): 1354mm
Leg Length: 775mm
Foot Width: 140mm
Weight: 12.1kg
CHARLI-2 Servo Torque: 10.5Nm
(2x per upper leg joint/1:3 gear ratio giving 63Nm)
Dynamixel EX-106+ (RS485 Asynchronous Serial)
1% (0.63Nm) servo torque per 1% (121g) overall body weight
Dims: W40.2xH65.1xD46
Servo Weight: 154g
Number of Servo's: 18 (legs only)
Leg Servo Weight: 2.77kg (legs only)
Arm Servo (x8) Weight: 0.28kg/0.5kg
(3.6Nm/6.3Nm each)
Head Servo (x2) Weight: 0.14kg (3.6Nm each)
Total Servo Weight: 3.69kg
Servo's accountable weight: 30.5%
(Note: Servo's accountable weight marginally higher than CHARLI-L due to 0.6kg weight reduction in CHARLI-2 version)
Rpm: 69.93 (@18.5V)
(Bear in mind Rpm is from EX-106+ datasheet spec, not AFTER the 1:3 geardown/ratio used on CHARLI-2 which would result in 23.3rpm)
Lower body weight: 6.8kg (53.4%)