Hybrid wheel / leg QUAD

Introduction
HTR has developed legged robot systems since 1998 with focus on energy efficiency and autonomy. Our recent developments in variable flexibility wheels for Martian and Lunar rovers enable a new approach to high mobility and optimal efficiency vehicles: The wheel / leg hybrid concept. High efficiency wheels are used for high speed / moderate terrain while leg mobility ensures obstacle negotiation, staircases and steep slopes. The result is a versatile, extreme mobility system that can respond to the most demanding terrain and obstacle negotiation requirements, while preserving record setting efficiency as set by HTR’s variable stiffness wheel concept.
Hybrid QUAD on steep, loose stone pebble slope
The large payload capacity of these vehicles (80 kg) and their efficiency (8h – 60km range) make them ideal for logistics support in a number of applications where prepared surfaces are not available. Such situations may be found in natural environments (forests, desert, etc) as well as in human-made environments ( house interiors with stairs etc).
The key issue for the wide use of such systems relies on their autonomy, which on turn depends on their energetics, ie their ability to operate with low energy requirements during their locomotion. This is difficult to obtain with such multi-dof systems as power losses often occur in oscillatory motion of their limps.
The key issue for the wide use of such systems relies on their autonomy, which on turn depends on their energetics, ie their ability to operate with low energy requirements during their locomotion. This is difficult to obtain with such multi-dof systems as power losses often occur in oscillatory motion of their limps.

The large payload capacity of these vehicles (80 kg) and their efficiency (8h – 60km range) make them ideal for logistics support in a number of applications where prepared surfaces are not available. Such situations may be found in natural environments (forests, desert, etc) as well as in human-made environments ( house interiors with stairs etc).

The key issue for the wide use of such systems relies on their autonomy, which on turn depends on their energetics, ie their ability to operate with low energy requirements during their locomotion. This is difficult to obtain with such multi-dof systems as power losses often occur in oscillatory motion of their limps.

Hybrid QUAD on steep, loose stone pebble slope

The large payload capacity of these vehicles (80 kg) and their efficiency (8h – 60km range) make them ideal for logistics support in a number of applications where prepared surfaces are not available. Such situations may be found in natural environments (forests, desert, etc) as well as in human-made environments ( house interiors with stairs etc).

The key issue for the wide use of such systems relies on their autonomy, which on turn depends on their energetics, ie their ability to operate with low energy requirements during their locomotion. This is difficult to obtain with such multi-dof systems as power losses often occur in oscillatory motion of their limps.

Posture regulation as function of terrain condition
The choice of the correct actuation and power control units are also of key importance. Hybrid QUAD takes advantage of HTR’s long test periods with a wide variety of electrical actuation solutions. Two energy-consuming key areas have to be addressed during operation of legged systems: Actuators working against gravity forces (such as the leg actuators supporting the body weight) and actuators performing oscillating motion (such as the leg actuators performing the fore-aft motion of the legs).
Hybrid QUAD on soft ground
Physical Specifications

Overall length

2130mm

Height

1257 mm

Battery autonomy

Minimum 8 hours

Total number of motors

12

Height at hip level

920mm

Width at foot base

450mm

Net full robot weight without batteries

67kg

Battery

12 kg

Payload

80kg

Speed

10km/h

Range

60km

Hybrid QUAD and HTR factory
Drone and Terrestrial Robot Command Platfform
HTR QUAD rover on loose sand slopes

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