CSE 480 Fall 2003 Group 1 Even more ESCs and H- Bridges • We tested the current draw on our servo and main motor: • Max current servo = 0.3A • Max current motor = 2A
Dec 22, 2015
CSE 480 Fall 2003 Group 1Even more ESCs and H-Bridges
• We tested the current draw on our servo and main motor:
• Max current servo = 0.3A
• Max current motor = 2A
Homemade Speed Controls
• http://www.math.niu.edu/~behr/RC/speed-ctl.html
• “Most home-grown ESC plans are by design simple. This also means that they will be, as a rule, less reliable and more temperamental than commercial units. An ESC is supposed to detect pulses whose width is varying a little bit, and convert those variations to a big voltage swing which controls the FET. All this has to happen in a nasty environment: vibration, interference from the motor, etc. It isn't a trivial job. “
• A few designs in the German Magazine, ElektroModell.
ESC using PIC Microcontroller ($??) http://homepages.paradise.net.nz/bhabbott/esc.html
Homemade H-Bridge (no break)• $1.60 1.5A, 8-DIP
http://www.robotroom.com/HBridge.htm l
Simple H-Bridge we built (3A)(untested)
PWM
5V
REF
1k
1k
1k
1k
MIN
Zetex ZHB6718 H-Bridge ($3.70)
Half-H/Full-H Drivers (~$2)
Cont.
Texas Instruments TPIC0107B ($4.28)
• 5A, 2kHz
• 20HSOP
Motorola 33886 ($6.22)
• 5.2A, 10kHz, 20HSOP
Heatsink Small OutlinePackage (HSOP)
• Our Prototype Board vs HSOP
MC33886 Development Board ($50)
Conclusions
• Anyone else find ESCs and H-Bridge designs?
• We could spend an entire semester just designing an ESC.
• This doesn’t even include the circuitry for the sensors.
• What level of abstraction should we use for sophomores? (Transistor level, IC level, ESC level)
Trying to find the right balance for the sophomore design project.
• CS portion is going to be decided on level of API abstraction.
• CE portion is probably under 25% since we’re not designing a CPU from scratch.
• Building a car from scratch could skew ME > 25%• Building an ESC from scratch could skew EE > 25%
The Optimal Balance
ME
EE
CE
CS