Background: Multirotor unmanned aerial vehicles (UAVs) are critically constrained by battery endurance, achieving only 15–25 minutes per charge in operational configurations — a fundamental limit driven by the electrochemical ceiling of lithium polymer chemistry. Piezoelectric energy harvesting (PEH), which converts structural vibration injected by onboard BLDC motors into usable electrical power, offers a mechanically passive, structurally integrated supplement requiring no additional rotating machinery. Methods: This systematic review synthesises 38 peer-reviewed studies and technical reports identified via PRISMA-ScR methodology across Web of Science, Scopus, and Google Scholar, spanning 2008–2026. Each study was critically assessed against five criteria: method type, experimental validation status, UAV platform, key quantitative result, and reliability designation (Highest/High/Medium/Low) according to an explicit evidence hierarchy. An original normalized power density analysis (mW/cm²) enables cross-study comparison on a common dimensional basis. Results: Three convergent design conclusions are established, two at Highest reliability. The central finding — arm-root patch placement outperforms motor-mount placement by 12.7–75× in harvested power — is replicated by experimental laser Doppler vibrometry (12.7:1, Perez et al. 3) and analytically verified Euler–Bernoulli FEA (75:1, Omar 5). An energy budget analysis reveals that the highest reported output (5.35 mW, four-arm flight experiment) represents approximately 0.002% of nominal hover power draw, confirming PEH as a sensor-power supplement rather than a propulsion augmentation strategy. Four critical research gaps are identified with explicit priority assignments. A costed four-stage roadmap charts the path from bench validation (Stage 1, ≤USD 320, 0–12 months) to multi-platform DRL-integrated flight systems (Stage 4, ≤USD 15,000, 3–5 years). Conclusions: Root-zone placement (first 20% of arm span from hub) and broadband conditioning are now sufficiently evidence-grounded to be treated as settled engineering principles. Magnetic plucking is identified as the highest-priority unexplored broadband strategy. The end-to-end in-flight demonstration gap is a resource and integration challenge, not a knowledge gap, making it immediately tractable for a well-equipped university research group.
OMAR et al. (Mon,) studied this question.