home  >  Hextor 24 September 2007

Hextor has been discontinued by Milford Instruments.
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    Hextor by David L Buckley - August 2001
    further information e-mail

    Hextor - six-legged walking robot with gripper/lift

    Designed by David Buckley and based around a Parallax BS2sx processor, easily programmed in Stamp Basic, the Walker comes with fifteen servos, twelve for the six legs, two for the gripper/lift and one for scanning with the Polaroid ultrasonic range-finder, power is supplied from a standard 7.2volt Nicad pack.

    The user programmable BS2sx is in overall control of nine co-processors. One deals with the keypad and LCD, one controls the ultrasonic range-finder, one looks for infra-red control commands from a standard (tv/video/hi-fi) remote control, while the main one runs Milford's Bug Commander Behavioural Operating System (BOS) which in turn has five co-processors running the servos.

    The removable board with the keypad and LCD can be used via a short umbilical for direct control of Hextor.

    For schools and novices there is a suite of over thirty BS2sx programs which show how to use all the features of the robot using the simple commands built into its operating system. The programs take you through all the steps required from flashing the LEDs to a full Behavioural Control program.

    The BOS firmware commands enable high level control, of walking using both Tripod Gait and simple Wave Gaits, and also the gripper/lift. The commands use simple ascii codes. eg "F" - Forward, "B" - Backward, "R" - Right turn, "L" - Left turn etc. Full control is available through these commands for adjusting the speed of the servos, the ride height, leg lift when walking, stride length and more, including direct control of each individual servo and interrogation of each servo's status and position in order to allow users to experiment with complex gaits and to have fine control over the gripper/lift.

    The fully commented Behavioural Control program (BC) for the BS2sx, written in Parallax Basic, allows the walker to be controlled from the keypad or a standard infra-red remote control, to jump to routines allowing the walker to wander about under program control using data from the Ultrasonic Rangefinder, or to execute user behaviour routines held in the BS2sx's internal EEPROM. The behaviour routines are run by a powerful extendable script engine which handles sensor testing and high level sequencing by using the high level ASCII commands already built into the BOS firmware.

    For Lab use the BS2sx may be bypassed allowing direct control of the Bug Commander BOS from a terminal or other control computer or the BS2Sx may be replaced by any pin compatible module such as the Parallax Javelin, a Java Stamp module, Parallax BS2p, BasicX-24 from Net-Media, or an Atom from Basic-Micro

    All the electrics and electronics may be shut down by the user program in the BS2sx microcontroller and the BS2sx put in sleep mode reducing the current consumption to a few microamps.

    Included on board are two LEDs for status indication, a sounder, two whisker connections and a bytewide header for other sensors and communications links. A range of daughter boards are available which plug onto the header and provide extra functionality such as voice control and prototyping areas.

    Since the walker comes ready equipped with an ultrasonic range finder and has a 300g/10oz gripper payload, the combination of the powerful BS2sx BC and the Bug Commander BOS means you can have your ALife research project up and running in short order.

    Hextor is available from Milford Instruments.

    Technical specification

    Model Number:		Hextor  Part # 5-780,	Milford Instruments Ltd,
    Overall Length, in.:	body 11, including arm+gripper 18
    Overall Width, in.:	body 7, over hips 8.5, over feet robot sat down 13.5
    Height, in.:		9.5 to top of US scanner
    Ground Clearance, in.	3
    Weight, with batteries and electronics, oz.:				1.6 Kg (3 lb 8 oz), ready to walk
    Payload Capacity (not including robot body & servo weight) oz.:		ready to walk User-Payload  1.5 Kg,  (3 lb 5 oz (53 oz))
    Speed on horizontal ground at 6V, in.sec.:	Theoretical 12, 	practical about 6
    Body Material:			5mm (0.2inch) foamed-core PVC sheet
    Leg Material:			5mm (0.2inch) foamed-core PVC sheet
    Standard Servo Model:			Supertec S03 - hips,elbow, gripper, US scanner; Supertec S06 - knees
    Servo Torque at 6V:			S03 = 4.0 kg-cm, 56 oz-in	S06 = 8.0 kg-cm, 111 oz-in
    Servo Speed @ 6V (sec/60 deg):		S03 = 0.23			S06 = 0.33
    Standard Included Servo Controller:	5 off - Milford intelligent 3-servo controllers, Serial, and can be interrogated for servo position.  
    Number of Controllable Servos:		15 (16 including US scanner)[15 servos included]
    (Standard Included Microcontroller:	Parallax BS2sx with Hextor control programs - may be user upgraded with BS2p or BS2px
    					PIC18F876 with Milford Behavioural Operating System (BOS)
    					5 off Milford intelligent 3-servo controllers - 12C509
    					Milford IR receiver/decoder - PIC12C509
    					Milford Polaroid Ultrasonic Scanning Rangefinder - SX18AC
    					Milford/Scott Edwards SerialLCD+Keypad  - 16F84A
    Prototyping Area for additional Electronics:			Bytewide Expansion connector to PortB of BS2sx - allows off board prototyping.
    Manufacturer Recommended Battery type/size for Servos:		7.2v 2000mAh NiCad racing pack regulated to 6v
    Manufacturer Recommended Microcontroller for Automonous/Remote Control Operation:	see above included controllers
    List Price:	see Milford Instruments
    Special Features and Notes:
    	The on-board firmware takes care of all the low level walking operations
    	and allows high level programs to be constructed in the included BS2-SX Stamp.
    	Direct control of the servos is included for advanced users.
    	Hextor comes with a suite of 27 program demonstrating how to use the included features,
    	and a suite of 7 BS2sx programs which allow fully Autonomous Operation, 
    		including script operation of all functions, 
    		Behavioural Control based on the Ultrasonic and Feeler sensors,
    		plus IR control from a standard remote,  
    	2 servos per leg, 
    	2 servo front arm & gripper mechanism, 
    	IR remote control capability, 
    	Ultrasound scanning head, 
    	power switch relays, 
    	expansion board socket, 
    	twin feelers, 
    	teaching LCD pendant, 
    	co-processor pre-programmed with our firmware, 
    	Parallax BASIC Stamp2SX, 
    	fully built and tested electronics board, 
    	pre-cut body parts from 5mm plastic, 
    	7.2V Nicad pack and charger.
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