Single Piezo-Actuator Rotary-Hammering Drill for Planetary Sampling
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Solution Overview
Problem
Conventional drills used for subsurface sampling in extraterrestrial missions are complex and prone to failure, often requiring lubrication that can contaminate samples and lead to erroneous analytical results.
Innovation Solution
A compact Single Piezo-Actuator Rotary-Hammering (SPaRH) Drill that uses a single piezoelectric stack actuator to simultaneously generate both rotary and hammering motions, eliminating the need for a gearbox and reducing complexity, while minimizing axial preload and power consumption to preserve sample integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotary motors are used for drilling, then rotational drilling motion is achieved, but device complexity increases and reliability decreases due to multiple components and lubrication requirements
Solution Approach 1:
The patent combines rotary motion and hammering motion generation into a single piezoelectric actuator system. The piezoelectric stack directly generates both rotational torque and axial hammering forces through its piezoelectric effect, eliminating the need for separate motors, gearboxes, and transmission mechanisms. This merging of functions into one actuator reduces device complexity and removes multiple potential failure points, thereby improving reliability.
Solution Approach 2:
The patent replaces conventional mechanical motor systems with a piezoelectric actuator system. Instead of using electromagnetic motors with mechanical gearboxes and transmission components, the invention uses the piezoelectric effect to directly generate the required mechanical motions. This substitution eliminates lubrication requirements and reduces the number of moving parts, improving reliability while reducing complexity.
2Productivity
If conventional motors with gearboxes are used, then both rotary and hammering motions are generated, but power consumption increases
Solution Approach 1:
The patent replaces inefficient mechanical transmission systems with direct piezoelectric actuation. The piezoelectric stack converts electrical energy directly into mechanical work with high efficiency, avoiding energy losses in gearboxes, bearings, and other mechanical transmission components. This direct conversion mechanism significantly reduces power consumption while maintaining drilling productivity.
3Ease of operation
If lubrication is used in conventional drills, then mechanical components operate smoothly, but sample contamination occurs leading to erroneous analytical results
Solution Approach 1:
The patent replaces lubricated mechanical systems with a piezoelectric actuator that operates without lubrication. The piezoelectric stack generates mechanical motions through direct electro-mechanical conversion, eliminating the need for lubricants that would contaminate subsurface samples. This substitution removes the harmful factor of sample contamination while maintaining smooth operation through the inherent precision of piezoelectric actuation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The SPaRH Drill achieves efficient and reliable drilling with minimal sample contamination, capable of acquiring pristine powdered cuttings and core samples from various media, including rocks and ice, with reduced power consumption and increased drilling efficiency, suitable for extreme environments.
Implementation Method 1
a single piezoelectric stack actuator having an electrical signal input port and a mechanical signal output port
Implementation Method 2
configured to provide an output mechanical signal simultaneously having both a longitudinal mode and a twisting mode
Implementation Method 3
configured to impart a longitudinal motion and a rotational motion simultaneously to a tool
Data Source
AI summary
A Single Piezo-Actuator Rotary-Hammering (SPaRH) Drill includes a horn actuator having high power piezoelectric materials and a flexure pre-stress to increase the actuators effectiveness. The drill is a low mass, low power, compact coring drill measuring 20-cm high by 7-cm diameter and having a total weight of 2 kg including drive electronics. Using an average power of 50-Watts, the drill basalt is expected to cut basalt at a rate of 0.2 cm/min down to depth of 10-cm and create cuttings and an intact core. The drill is expected to operate under different environments including Martian ambient (6 Torr and down to −50° C.), and liquid nitrogen temperatures (77 K) and low pressure (<<1 Torr) to simulate lunar polar and Europa conditions. Materials expected to be sampled include Kaolinite, Saddleback Basalt, Limestone, Volcanic Breccia, Siltstone, ice, permafrost and layered rocks with different hardness.