Vectoring robots with Omni or Mecanum wheels
How Vectoring Movement is Possible
Vectoring movement is achieved through a sum of forces generated by each wheel. In Figure 1 below, you will notice that for the robot to move to the right motor A will need to move in the negative direction and motors B and C would move in the positive direction.
This diagram also shows why motors B and C must be reduced while moving sideways. Motors B and C must have the same power to negate the forward and back movement while motor A must generate the same amount of sideways force as the sum of B and C.
Figures 2 and 3 show the two distinct types of omni wheels. Both Omni wheels and Mecanum wheels provide traction in normal wheel movement as any other wheel would. however, what makes these wheels special are the small rollers along the wheel's edges. These wheels are designed to provide a minimum amount of friction sideways allowing the wheels to move in any direction.
Omni wheels have smaller rollers on the edges that move completely perpendicular to the wheel itself. With this type of wheel they must be mounted perpendicular to the center of the robot as seen in Figure 1.
Mecanum wheels are unique in that the small rollers are at a 45 degree angle. This allows them to be mounted like normal wheels but provide the name style of movement as Omni wheels.
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4WD Omni-directional Robots
We have several options for four wheel omni-directional robots. They use mecanum wheels or omni wheels mounted at a 45 degree angle. By changing the speeds and directions of the wheels you can achieve movement in any direction! Due to the style of the wheels it is possible to move the wheels in a standard "tank style" motion to drive normally when needed.
These robots also work well for supporting high payloads since the wheels allow them to turn with very low friction. See the load ratings on the robot page for an idea of the payload.
4WD Vectoring Robot Platforms
3WD Omni-directional Robots
Our 3WD omni-directional robots our double-row omni wheels, allowing it to vector in any direction.
3WD Vectoring Robot Platform
Programmable Tri-Wheel Vectoring Robot Kit - IG32 Medium Duty SB
Programmable Triangular Omni Wheel Vectoring Robot - IG32 DM
Controls and Specifications
Motors and Motor Mounts
We have mecanum wheel robot kits that use IG32, IG42, and IG52 motors. Below are the motors that we recommend using with these platforms, though you can use different motors if you need more speed or higher payloads. All motors are available in wide range of RPMs and some are available with a built in encoder option. For a detailed list of our available motors please see the link below. The Omni wheel based chassis is available in both IG32 and IG42 variants.
- 32mm 190 RPM 24V IG32 Gear Motor (TD-015-190)
- 42mm 240 RPM 24V IG42 Gear Motor (TD-016-240)
- 52mm 136 RPM 24V IG52 Gear Motor (TD-048-136)
- IG32 or IG42 Motor Mount Tube for Omni Wheel Chassis (TD-056-342)
Click here for a listing of our available motors.
Wheels and Drive Shafts
Our Mecanum wheels are available stand-alone or paired with compatible wheel hubs. All wheels listed below fit any of the nexus aluminum hubs. The 4" mecanum wheels also fit the SDR manufactured flush mounted hubs.
- 4 inch nexus Robot Aluminum Mecanum Wheel - Ball Bearing(TD-090-100)
- 4 inch nexus Robot Aluminum Mecanum Wheel - Sleeve Bearing(TD-169-100)
- 6 inch nexus Robot Aluminum Mecanum Wheel (TD-090-152)
- 8 inch Nexus Robot Aluminum Mecanum Wheel (TD-090-203)
- SDR Flush Mounted Hub with 6mm Bore (TD-107-006)
- SDR Flush Mounted Hub with 8mm Bore (TD-107-008)
Nexus Aluminum Hubs
The Omni wheels are shafts are sold together as one unit. The shaft comes with a bearing and lock collar that fit into/onto the motors and motor mounts. The wheels are 4 inch in diameter. The traction wheels are made of durable urethane to help grip the floor. The wheels are available in two types; single row and double row. The double row wheels provide smoother operation but both work great.
- Nexus Omni-Wheel and Shaft Assembly - 6mm Bore (TD-145-006)
- Nexus Omni-Wheel and Shaft Assembly - 8mm Bore (TD-145-008)
Below is a diagram showing how the mecanum wheels should be mounted and which direction to turn the wheels for vectoring movements.
Motor and Speed Controllers
We offer a variety of motor controllers to allow for simple operation of the robot. The motor controllers are independent of the chassis type (Mecanum or Omni). To provide vectoring movement it is required to have one motor channel per motor.
Dimension Engineering's SyRen 10 is a versatile motor controller that is suitable for robots up to 30 lbs. The SyRen 10 is able to be controlled over a 5V TTL serial signal or over RC. One big advantage of the SyRen 10 is that it is compatible with the DE Kangaroo motion controller (TE-180-000). The Kangaroo allows the SyRen to receive feedback from an encoder and to operate with true speed control. For heavier robots, the SyRen 25 is available that can support up to 180 lbs.
To provide a inexpensive option we can also provide our own single channel PWM motor controller. Our PWM motor controller can only be controlled with a 5V TTL PWM signal and direction bit. The PWM motor controller is intended for small, light weight robots such as these vectoring robot kits. They are easy to use and can be controlled with any micro controller based platform.
Recommended Motor Controllers
Controller and Controller Interface
We offer three main control options for vectoring robots: Radio Controlled, WiFi, and wireless serial (xBee).
R/C (Radio Control)
For R/C control of the robot, although the motor controllers listed above support RC you will still need a micro controller on the robot in order to handle the motor mixing necessary to achieve vectoring motion.
For accurate robot control, the remote will require at least a two axis joystick/control and a signal switch to change driving modes if desired. Below is a recommended listing of our R/C remotes.
- Spektrum DxE Transmitter with AR600 Receiver (TE-113-005)
- Spektrum DSMX DX6i Transmitter with AR610 Receiver (TE-113-006)
- Spektrum DX8 Transmitter with AR8000 Receiver (TE-113-008)
- Spektrum DX9 Transmitter with AR9020 Receiver (TE-113-009)
Here at SuperDroid Robots, we offer two WiFi control interfaces. We sell an Arduino based control interface package (TE-900-003) that provides an Arduino Mega, Ethernet shield, SDR Breakout shield, voltage regulators and 4 TTL Relay Board (TE-010-405). The control package includes the source code for the control software and the Arduino firmware needed for operation of the robot.
We also carry a cheaper WiFi Custom Control Interface Package (TE-900-002) of our own design that is pre-configured for your robot. The package includes a router, one of our custom control boards, voltage regulators, iPocket Ethernet to Serial Converter, 4x TTL Relay Board (TE-010-405), gamepad and custom control software.
Please see our WiFi Control Interface Support Page for more information.
Wireless Serial Control
Wireless serial control is achieved through an xBee radio. Wireless serial is currently only available if you choose an Arduino based control system. The xBee radio connects to the Arduino through the Arduino Wireless SD Shield (MCU-064-000). A Wireless Serial Control system is available by request. Please contact us for more information.
Please see our Wireless Serial Support Page for more information.
The final item you need to make your kit complete is a hardware package. It includes nuts, bolts, washers, cable ties, and cable hold downs.
- Hardware Package (mounts most components to the base robot) (TD-021-000)
- Servo Standoff Mounting Hardware (TD-024-000)
In order to make your robot autonomous, you will need to add sensors. Sensors can always be added or removed at a later date but always be mindful of how the sensors interact with your micro controller. Some sensors operate under I2C, some SPI and some analog. See our Sensor Support Page for more information.
- Accelerometers, Gyros, GPS, and Compasses
- Contact Sensors
- Current Sensors
- Force Sensors
- Gas Sensors
- Optical Sensors
- Sonar Range Finders
- Temperature and Humidity Sensors
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