9. Motor Driver¶
In order to drive the MYO-Muscles, a motor driver board is provided. This is illustrated in Fig. 9.1. The motor driver board is supplied with 24V and communicates with the MYO-Ganglion via a 5MHz SPI connection. It provides sockets to connect the MYO-Muscle motor as well as a further connection for the spring-displacement sensor. For further hardware developments and other extensions, there is also a CAN interface and a micro-USB connection. However, they are not required when building a Myorobot.
9.1. Spring Displacement Sensor¶
To measure the displacement of the spring (a proxy for tendon force), a spring displacement sensor is connected to the motor driver board. The sensor is supplied via the motor driver board and connected via a 6-pin JST connector  as depicted in Fig. 9.2.
9.1.1. Wiring Scheme: Spring Displacement Sensor - Motor Driver Board¶
This cable is NOT symmetric.
|Displacement Sensor, pin #||1||2||3||4||5||6|
|Motor Driver Board, pin #||5||3||2||1||4||6|
9.2. Driver Board Mounting¶
To illustrate how a motor driver board is mounted on the MYO-Muscle please refer to Fig. 9.4. The connector for the spring displacement sensor should be facing the spring. Two screws are sufficient to mount the motor driver board on the MYO-Muscle as shown in Fig. 9.4.
The motor driver board has to be connected to the MYO-Ganglion board using the 5-pin JST connectors  . Depending where the motor driver board is plugged in (SPI0, SPI1, SPI2 or SPI3) the associate MYO-Muscle can be addressed with the corresponding index the flexrayusbinterface. In other words, the address of a motor driver board (and therefore the MYO-Muscle) is dependent upon the SPI connector it is connected to (see Table 9.1).
|SPI Connection||Address / C++ index|
9.3.1. Wiring Scheme SPI Connector: Ganglion Distribution Board - Motor Driver Board¶
|Ganglion Distribution Board, pin#||1||2||3||4||5|
|Motor Driver Board, pin #||1||2||4||3||5|
|||The 6-way JST SH series connectors are available from Farnell Components, Farnell-number 1679112; connecting wires with pre-crimped connectors are available via RS components (300mm RS-number 311-6675, 150mm RS-number 311-6653).|
|||The 5-way JST SH series connectors are available from Farnell Components, Farnell-number 169111; connecting wires with pre-crimped connectors are available via RS components (300mm RS-number 311-6675, 150mm RS-number 311-6653).|